It's already been pointed out that your question is perhaps a little too broad. So you may want to edit and narrow it down.

However, I'll focus my answer on a specific paragraph which seems to be your biggest concern:

I am the primary tank of the team so I need my AC high. In the adventures however, there seems to be so many opponents I soak up (usually 3 at a time engaging) that I am almost in low health before we win.

Tanking is not purely about AC. And if you obsess about this single aspect it will hamper your effectiveness.

An important aspect of tanking is control.

• When fighting unintelligent creatures, it may be easy enough to put yourself front and centre and they'll attack you. But more intelligent opponents may choose to ignore you and attack "better" targets instead. Champions tend to be focused more on raw power, so you'll have to rely on your teammates to cover this.
  • But you might want to consider the Protection fighting style, which defends nearby allies by imposing disadvantage on an enemies attack roll.
  • Sentinel is a good choice of feat.
  • Mobile can be a useful feat making it safer to move around during combat.

AC suffers diminishing returns

Basically + 1 AC reduces average damage per attack by less for each point gained. The reasons are:

• Natural 20 is a guaranteed hit (+1 AC may in extreme cases may have zero effect of the range of rolls that succeed or miss).
• The critical effect boosts damage of a high roll (so AC increases reduce average damage / attack by less for each point).

Something that can be far more effective is imposing disadvantage or removing advantage.

At the extreme end, if an enemy needs to roll 20 to hit: +1 AC has zero effect on the odds of doing damage. But disadvantage reduces the odds from 1 in 20 to 1 in 400. And removing advantage reduces the odds from just under 1 in 10 to 1 in 20.

The benefit of AC is that it's passive. It's "always on" and available to avoid damage. It doesn't get "used up" and doesn't consume actions.

However, something seriously worth considering in place of a small AC boost is the Lucky feat.

AC doesn't help at all in some situations

Many magic attacks don't require an attack roll, meaning AC is useless. So you may want to consider alternative forms of damage avoidance.

• Shield Master is an excellent choice.
• Again the Lucky feat is noteworthy.

(Though I'm a little skeptical of the benefits of the Resilient feat.)

That said, unless you're in a very heavily combat and tactics focused group, you shouldn't need to min/max your abilities. In combat, teamwork and cooperation are far more important. And there's plenty that goes on in the game outside of combat.

Outside of Complete Scoundrel (14) and Sharn: City of Towers (168), the prestige class exotic weapon master is unmentioned beyond its original appearance in Masters of the Wild (53–4) then its revised appearance in Complete Warrior (30–1). Neither Scoundrel nor Sharn offers anymore insight than Warrior into how to use the exotic weapon master prestige class's extraordinary ability exotic weapon stunt (uncanny blow). That means you're stuck reading the special ability and making a choice.

What uncanny blow says…

The extraordinary ability exotic weapon stunt (uncanny blow) says

When wielding a one-handed exotic melee weapon in two hands, the character can focus the power of his attack so that he deals extra damage equal to his Strength bonus ×2 instead of his Strength bonus ×1-1/2. If he has the Power Attack feat, he treats the weapon as two-handed for purposes of determining his bonus on damage rolls. (31)

(If that last sentence strikes you as a largely unnecessary reminder, it should. This reader suspects that the precise wording of the 3.5 revision's of the feat Power Attack (PH 98) was still being decided when Complete Warrior was published, Warrior appearing on shelves only 5 months after the revised Player's Handbook.)

Anyway, the Player's Handbook description of the bastard sword, in part, says, "A bastard sword… is an exotic weapon. A character can use a bastard sword two-handed as a martial weapon" (121). And the bastard sword appears on Table 7–5: Weapons under the heading Exotic Weapons under the subheading One-handed Weapons (117). For this reader, that's enough: the bastard sword is always a one-handed exotic weapon that can—it just so happens and if the wielder so chooses—also be used as a martial weapon if the wielder employs it two-handed.

Thus this GM would rule—perhaps even a little reluctantly, depending on the optimization level of the campaign and the possible outcome of such a ruling—that a creature that's proficient with all martial weapons, that enters the prestige class exotic weapon master, and that picks the special ability exotic weapon stunt (uncanny blow) can use that special ability with a bastard sword that the creature wields in two hands, despite the creature not possessing the feat Exotic Weapon Proficiency (bastard sword) (PH 94) yet possessing the feat Weapon Focus (bastard sword) (PH 102) (perhaps through a workaround like the swordsage's extraordinary ability discipline focus (Weapon Focus (Diamond Mind)) (Tome of Battle 16).

…Then there's some Sage Advice

The Dragon #316 Wizards Workshop column "Sage Advice: Equipment and Combat Official Answers" (100–4) includes two exchanges relevant to the extraordinary ability exotic weapon stunt (uncanny blow).

Question

So when is a weapon “two-handed?”…

Answer

Table 7–5 in the Player's Handbook lists weapons as light, one-handed, or two-handed strictly as a matter of convenience. These size categories [i.e. the effort required for a creature to wield the weapon] are always relative to the wielder’s size….

When the combat rules speak of “two-handed” weapons, they’re referring to how the weapon is being used. A Medium character using a Medium longsword in two hands is using a “two-handed” weapon. The same character using a Medium lance in one hand while mounted is using a one-handed weapon. (101–2)

So, according to this advice, a creature that's wielding a bastard sword in two hands is using that bastard sword as a two-handed weapon. That means the special ability exotic weapon stunt (uncanny blow) can apply to the bastard sword, and we're good to go, right? Not so fast. The very next question is this one:

Question

Exactly when is a weapon light, one-handed, and two-handed?…

Answer

The bastard sword, lance, and dwarven waraxe are all two-handed weapons that can be used in one hand under the correct circumstances (the bastard sword and dwarven waraxe are shown on Table 7–5 as one-handed exotic weapons, but they’re really two-handed weapons). Treat all three of these weapons as two-handed weapons when determining who can use them and how. For example, a Small character cannot use a lance or bastard sword made for a Medium creature, even when mounted (in the case of a lance) or when the Small character has the Exotic Weapon Proficiency (bastard sword) feat. (57)

(Emphasis in answers mine. The Sage at the time is Monster Manual primary author and dnd-3e co-designer Skip Williams.) So, in sum, the advice tells the reader that Table 7–5: Weapons lists the bastard sword and dwarven waraxe as one-handed weapons only for convenience and that outside of combat, those weapons are totally two-handed weapons, even though in combat those weapons can be considered either one-handed or two-handed weapons depending on how they're used.

So an argument can be made either way. On one hand, the description of the stunt uncanny blow could be describing how a creature must be using the exotic weapon in combat, so the stunt totally falls under the first ruling, making using the stunt with a bastard sword that's used two-handed legit. On the other hand, the description of the stunt could be describing in the abstract the kind of weapon that the creature must wield to experience the stunt's bonuses, and that description is independent of the weapon's wielder, in which case the stunt's not legit for use with the bastard sword or dwarven waraxe because, technically, no matter how they're used those weapons are always two-handed weapons.

This reader tends to favor the former rather than the latter: the universe is hard enough on the mundane warrior without—as it seems to this reader—double-secret rules prohibiting players from their PCs being ever-so-slightly improved and more versatile axeman or swordsman.

Note: These Sage Advice exchanges are repeated nearly verbatim by the Main FAQ on pages 48 and 57, respectively. Issues with the FAQ can be viewed in answer to this question.