I don't do tournament play, but IMO Eldar are overpowered in the current codex.
The low T is a downside especially for characters / HQs
The poor save of mesh armour is only an issue if you use guardians, and no worse than many other codexes like AM, Orcs, DE, etc
Nothing better than AV12 could be considered an issue I suppose, but with the hull point system less so than in previous versions.
But we have a lot of really good options for increasing our durability:
-Access to Psychic powers like fortune and Invisibility
-Holofields / Sprit Stones / Ghostwalk Matrices for our vehicles
-putting HQs on jetbikes
-Jump-shoot-jump abilities of battlefocus, jetbike and warp spiders enabling them to get into cover / out of LOS
-Wraith units
I would love an assault vehicle, but because it feels fluffy to me, not because we are rubbish in assault without it. Striking Scorpions (infiltrate, stealth and heavy armour), WraithKnight (speed/durability) and to a lesser extent Banshees (speed) all have ways of getting into combat safely without using a transport.
And then of course we have some frankly ludicrous units in terms of points value:
Scatterbikes. Fastest troops in the game. Shootiest troops in the game. and one of the most durable troops in the game. In addition to totally outshining any other troop choice I can think of, they also outshine a lot of fast attack and heavy units other codexes can field.
Warp Spiders. Ridiculously quick, Flickerjump is just amazing. and their guns are pretty spesh, too.
Wraithknight. Better than an Imperial Knight, and much cheaper.
Add to that the general speed of our codex which makes it so forgiving to play, and you've got a very powerful codex indeed.
In previous editions, you did need to work the synergy of different units to get the best out of Eldar. Nowdays any muppet with half a brain can just load up on jetbikes, spiders and wraihtknights and more often than not come away with a victory.