I fully agree with ValihrAnt that phase 2 should be more valuable.
However, I do not think that just the blacksmith upgrades are the solution to this. To support this, I would like to say that if you do the first defence and offence blacksmith upgrade, your troops are probably only equivalent to an unupgraded army that is 15% larger in size. To get this advantage, you invest in an age up(500F,500W), building a blacksmith(200w), the upgrades(600F,400M+400W,400M) totalling at (1100F, 1100W,800M). What I am neglecting is that p2 also gives different options, but just for doing blacksmith upgrades p2 is not worth it.
I would like to see a different solutions to the problem like: Moving some champions to p2, moving unique techs to p2, moving unique buildings to p2(Theatron, persian, mauryan, gallic and spartan ´palaces´). What also might be an option is giving each unit a 10%( or respectively 5%) attack boost per age advancement and to compensate put the attack upgrades at 5%(respectively 10%) increase and 1/3rd(respectively 2/3rd) of the cost.
Response to soloooy0: I think that could help but I would suggest it would only be part of the solution. So it is an upvote for me, but I think we still need more.