Quit rushing and using tactics which will be nerfed in a week and try to have some fun.
You don't have to rush or use anything but basic tactics (build troops, move them towards enemy, obliterate enemy), and I personally don't use any known exploits, like loading up troops with tons of jewelry or kits (stuff that should get nerfed). I build entirely normal troops.
And I do have fun beating up the AIs - it's just way too easy. If I chilled and built up even more before finally attacking, it would be even easier because my troops would be exponentially more devastating.
At some point, AIs must be thrashed. Either they declare on you, poach something you want, demand something ridiculous, look at you funny - whatever it is - they must be punished, usually by me exterminating them like vermin.
4 games on extreme so far here, no difference, it's easy like any other difficulty setting.
PS: I'm not rushing either, i'm a builder, but at an certain point it makes no sense to keep building up.
I'm a builder too but there just isn't that much to build. I can get thru the tech tree pretty quick, to the point of having the end of tree techs in several trees and branches (some branches don't have much to them or much point to them either, but I still research the crap!), and be researching/learning level 10+ spells. Once you get rolling in Elemental it's like a runaway freight train.
I usually have so many resources rolling in that there's not much point in bulding anymore, except to build troops, which leads to "hey, my troops look pretty kick ass and designing parties/squads of uber troops is actually kinda fun - now to try them out on something," which leads to, wow, I just rolled an entire AI empire in 10 turns and now have all these new beefy cities producing even more resources. What next. I wonder. Rolling the wandering monsters isn't all that interesting because all you ever get out of it is gildar you don't need - and after slaying everything in sight just to have repops almost immediately, you start thinking, maybe I'll wipe out some mobs where there is a point - the AIs....
The builder side of the game just isn't compelling enough for me to want to sit around and build for ages like I would in GalCiv2 or Civ. In those games, I want to colonize every possible planet or build cities in every empty space, build them up, tech up, THEN finally get around to figuring out how I'm going to win. This is missing in Elemental to me. In elemental I wanna build a tight, defendable empire, build up a little, then expand thru violence. Totally not my style at all.