Angels have a few things going for them, but you're right that they're generally sub-par.
Advantage 1 - Resists: Angels get more built-in resistances than any other subtype except demons (and if demon is an option for you, angel probably isn't).
Advantage 2 - Alignment: Angels can be chosen by pretty much any non-evil summoner. Agathaions and especially azatas are pickier about who they'll work for.
Advantage 3 - Flight: Flight is something just about every eidolon is going to want eventually (except possibly ranged weapon eidolons), and angels get it for free. Admittedly, so do azatas (angels' main competition in the eidolon subtype department), but it's still a reason to look down (literally) on most other subtypes.
Generally speaking, angels are the go-to choice for summoners who want an azata but either 1) aren't "ideologically pure" enough to recruit one, or 2) want to trade some damage potential for tankiness. Also, angels are still better than archons in almost all cases.
There are generally two optimal paths for building unchained eidolons: a weapon-wielding biped, or a pouncing quadruped (serpentine forms have some unique options but ultimately aren't as effective). Azatas are the undisputed champions in the biped category, but if for some reason you don't want or can't take an azata, an angel is one of the better remaining biped subtypes.
Best Answer
Throw anything in Pathfinder reads:
So, a character with this feat can throw improvised weapons (things that are not intended as weapons) e.g. a purse, a rock, a stuffed moose head, a water melon and so on, without taking -4 on attack rolls.
This feat does not bestow upon a character the proficiency to throw actual weapons (ranged or melee), e.g. a shuriken, a javelin, a longsword, a mace and so on. Thus, a character with the Throw Anything feat will still get the regular -4 non-proficiency penalty when throwing a shuriken. Unless that character has the Exotic Weapon (Shuriken) feat, or is a monk.
As a side note, the only type of character who usually jumps at this feat is the alchemist, because of the +1 bonus to thrown splash. But a barkeeper with this feat and a +2 Seeking Corrosive Moose Head of Returning (corrosive because of the bad breath, you see) would sure be material for a memorable character!
The are rules for throwing melee weapons read as follows:
This is pretty severe, and with the RAW going against, I'd be extremely reluctant to let a medium creature with the Throw Anything feat toss scimitars with the scimitar damage and crit threat and without the -4 non-proficient penalty.
Based on the above, I'd reason as follows: Since Hill Giants, who are both Large and accomplished rock throwers do 1d8 with their rocks, an improvised medium thrown item should do 1d4 points of damage. If the character had the Throw Anything feat, I'd let the -4 penalty go, but still say that throwing a scimitar was a standard action and the crit range was 20x2 (instead of 1d6 and 18-20x2).