Ah, interesting!
If that's so, I'd say that melee and recon classes/promotions are alright. Different players use different unit types.
I expect that you are right about that.
but from my point of view
it's just that when using melee or mounted I'm always stumped on what to chose. (vengeance for bard or for the aura-class... but all other promotions are not really useful - and sometimes the heal-while moving.. but only if I have high affinity spells) or assault : I find that I usually use champion (the one that give +20%str + chance of battle stance) or death knight.. none of the others (I may use magic knight... but only as a second discipline if I ever get as far in the levels.)
So I like horses for their mobility, and for death knight, but when I have recon units I'd rather have recons... losing the 1 mvt is worth it when you take into account that most early-mid game is wildlands (so recon has easier time with animals and mounted has same issue of city attack than recon) and you get access to +4str!.
and they have time to accumulate experience until the mid game, when city attacks are necessary.
by then, melee would be useful, but they are slow, and have less xp (couldn't feed on bards as much).. so I often don't use them.
for recon, I never have issues, all disciplines are good, some more than others, but they are good.
for disciple, I can also manage.
for Mages : a few "sage" for the towers / and the others are all : +%damage class or dragon . once per game I use the "+aura" class.
ranged... I found that there is no synergy on arcane archer and attacking (like for melee : the class that gives +2str is not linked to the attacking discipline);
I find that for archers, the support discipline+class is the best one. but then they become hard to level.
I think giving archers +% city attack could help them (their are few units that can attack despite there being walls !!)