Txurce
Deity
I used to really like Legions, I would make iron working my 6th or 7th tech, build them really early and just dominate. What I've realized is that you can do that with regular swordsmen too. Legions are good mostly because they replace a good unit. There isn't really anything game changing about them, at 2 movement its tough to build roads with them.
March was suggested above and would have great synergy with road construction. Currently I often think about building a road but decide to spend the turn healing instead. With march you could do both
Early swordsmen are what I beeline for now as well. But the problem with giving the Legion March or anything else that's significant, is that Rome does well enough already.