I agree with most everything said in the responses. The only thing I wanted to emphasize was the setting - a prison island. I felt the penny pinch on the gold too, and yes I resorted to thievery, but both of those things felt organic considering the setting ... a prison island. I can't repeat that enough lol. Everything from "the setting is glum!" "Everyone is out for themselves" "It's hard to find gear" "This is hard" comes back to the RPG element that we're playing in - a PRISON ISLAND. The odds are stacked against you, and for me, that feels rewarding when I overcome them.
That's not directed at gameplay mechanics though, those should be balanced, but as far as gold/gear go, I think it's a valid point.
WRT Summoning, I was also disappointed with this, but I feel like I was using it wrong. I would often summon totems where enemies could easily get to them - eventually I would summon them way in the high ground. That's bonus damage, and a HUGE field of fire. I would also start summoning based on terrain - at first, I always went for water/fire elementals because I thought that'd be the strongest, right? Eventually, I summoned them based on the enemies weaker armor. Likewise with incarnates - a fire incarnate isn't as useful as a regular one when the enemy is weak on armor. So you get to adjust to the terrain/situation. It can still feel lackluster in comparison to giant wizard combos or rogue/ranger burst, but if you're a man of chess, you may enjoy the long-game summoner brings to the table. And at WORST, you spent 2AP to block 2 of their AP (assuming they attacked to kill it). Not great, but not terrible either. AP is a chief resource in these battles and trading 2 for 2 is a wash, not a loss.
Bullrush is insanely useful though. Battering Ram is nice for positioning and knockdown, but they need their armor down. Blitz is nice for gap closing/positioning, but can be less predictable, and costs more. Pheonix Drop is great for positioning and fire immunity. And all 3 get you to move 1 time each, for 3 memory slots, and a situational secondary.
Bullrush, meanwhile, gets you 4 uses for 1 memory slot, scales off your primary stat, and is dirt cheap. Whether you're a kiting wizard/ranger, positioning rogue, or warrior trying to get people in range of WW or Cripling Blow, that's just great return on the money.