[RPG] Increasing Weapon Die Size

If you haven't taken the Toughness feat, I recommend it -- at the beginning of each tier, it's 10% of your total hit points, which is not bad. Also think about Durable if your problem is running out of surges. Battle Healer is also quite good, since it gives you a bit of healing every time you heal someone else. Dwarf Battle Priest would do the same thing, and those two stack.

Another tactic: work on your defenses. Battle Cleric Armaments gives you light shield proficiency plus a better weapon. Looking ahead somewhat, there's the Battle Chaplain paragon path, which also gives shield proficiency, but I don't think it's otherwise all that great. Still, it gives you a mark, which is good if you want to keep being a defender.

If you want to try something a bit out of the box, think about polearms. You lose some of your defender ability, but you wind up saving yourself a ton of damage. Hafted Defense makes up for losing the shield. Polearm Flanker means you'll hit more often... and as a Strength cleric, you're dependent on hitting for much of your healing.

It depends on what you are looking for specifically. These weapon groups are generally the "best" for non-specialized builds. The other weapon groups do not have nearly the same power and/or feat support..

Heavy blades have the best proficiency bonus, this will lead to more hits and great DPR. As a fighter it will also help you enforce your mark by hitting more. Requires a moderate to high dexterity.

Axes - Requires a moderate investment in constitution. Not quite as much DPR as hammers but there are a lot of high crit weapons so your damage output will be spikier. (Doing 60+ on a crit can be a lot of fun)

Hammers - Requires a high investment in constitution. They will have the highest DPR in paragon levels and up thanks to Hammer Rhythm (does con modifier damage on miss)

Polearms - You will pay for the reach with a lower DPR per hit. However the increased reach may mean that you get more swings. The Paragon feat Polearm Gamble gives you threatening reach (more or less). Requires some wisdom.

Remember that strength and constitution feed the same defense (Fortitude). So if you use Axes or Hammers you are almost certainly hurting your Reflex and Will defenses compared to a fighter using a heavy blade or polearm.

Within each weapon group its pretty easy to spot the optimal weapon for yourself. Whether one handed or two handed, there is also a superior version in the Adventurer's Vault. The key is deciding whether you want to spend a feat obtain the superior version. Typically the superior version grants you +1 damage on average. If you are short on feats, its better to spend a feat on Weapon Focus (+1 damage/tier) than Weapon Proficiency. A striker should probably spend every feat possible to pump up their DPR while you, as a defender might wish to prioritize other things.