Errr...guys, no...Attila is:
a. better optmized than Rome 2
b. a better game overall
A good read on the matter:
https://www.rockpapershotgun.com/2016/01/04/best-total-war/
As if Charlemagne worth 15 euro...errr...can't say. I rarely buy games outside sales. So i still don't have the Atilla DLC's yet (but i can say that i have every other Total War games)
Personally, i like a lot more the two Shogun games, followed closely by the original Rome, the Medieval games, Attila, Napoleon, Empire and my least favorite being Rome 2 (was a mess stayed a mess).
Despite me loving the original Shogun, i ended up loving equally its sequel. Shogun 2 with all its expansions is truly worthy of the name Total War and probably doing right what Empire could not: a proper firearms era.
But if you are on a tight budget and want the game - buy in a sale or a bundle.