It's no secret that ecumenical is not meant as a solo pve build unless paired with something else. You do have options if you pick up mounted magery, no you wont be able to kill mobs as fast as a melee fighter, but thats the same case for an MA. As far as the casting from horse back you need to use a much larger kiting circle than an MA would need. It's difficult but its doable.
Don't expect to be able to farm like an MA that's like trying to compare foot fighter to an MA. For farming the foot fighter is faster with lower tier mobs but the MA has more survivability with higher tier mobs (in the open world obviously, they're useless solo inside dungeons for most situations)
I hate to sound like a broken record but in MO your race will affect what you can play efficiently. It's part of the game mechanics and we can argue about wether it's a good mechanic or bad mechanic but that's a pointless argument.
My Advice to OP:
If you're playing a human and are dead set on not rerolling (which is perfectly fine). I'd recommend you temporarily drop your psy and respect it into STR and play your toon as a hybrid until you've farmed clades up to your liking.
p.s. From what I've gathered, the person that puts the mob into mercy is the one who gets the highest clade from it. This could be wrong but it's what I've noticed so far.