I love regional troops in total war, to be honest, a tw game without feels bland and pointless to me. But in pharaoh they are just a bit too good and to me it's always hard to justify factional troops. Why slowly build 3 different buildings in precious capitol slots, when you can just get one building that gives you tiers 2-4 of all unit types plus hefty XP bonuses? My first step to mitigate this issue is to break up the regional recruitment centers and give them some downsides. This way there is more of a complex tradeoff between recruitment buildings.

I have a confession to make, I think ¾ factional unit recruitment buildings are meh. Let me explain:
In general there are four types:
Infantry - usually too many levels to build before you get one or two useful units.
Ranges - usually very limited roster that is easily replaced with natives
Stables - high level building that gives 1 or 2 iffy units
mix - good selection of crap that not only block your minor settlements from producing their max output AND further debuffs the diminished output.
Depending on faction 0-2 of these are good or at least situational. But overall, these suck.

In my opinion this is one of the reasons why most armies in Pharaoh consit mainly of Native units. In theory this would be interesting, but most wars are fought within a realm/theatre so what the players sees is fairly uniform.