To Battle Cry: As beastmaster you are able to tame a Great Wolf. This one has the Howl, which is similar. I usually play on Ridiculous Mode, where this skill is realy needed cause of massive monster HP. On normal you could be right ... i think over it
To Evoker: I explained it, with the Ring of Ash, Evoker IV, Volcanic Rites, Spellstaff or similar items a mage was to powerful with firemagic. My changes run to usually +75% Spelldamage for a high skilled mage ... this should be enough. Archer or melees dont have so much power to hold the balance.
Summoning: The young and regular Elemental are really weak and low leveled. The Ancient and real Elementals are heavy, you allright, but they are on the same stage as on the standard skill tree and costs lot of mana. The summon level bonus is the same as standard.
But thanks for your thoughts, i'am not finished with it and also not really satisfied with all changes. Summoning was one of it
The Soulbound Armor is treasure of an medium quest and soulbound items can be summoned with a rare scroll wich can be found.
My Epic Quest is a Fight vs. 4 Level 16 Elder Dragons, one Fell Dragon, one Strorm Dragon, one Ashwake Dragon and one Clambercoil Dragon. If you win, they offer you to join your army. In one game i encouter this quest on Level 17 with my 6 Hero Army and won
Just some feedback on your tweaks: Fire damage is subpar to Water Damage, as Evoker/Warlock you should be casting blizzard to crush those high number AI units. Fireball is weak compared to it, even before your nerfs. So they are not really necessary, and if you want others to use your mod I would suggest leaving that out 
(the less changes the better)
I play on ridicilous too, and have never needed howl or beastmaster But this is a fun addition and if you tweak the timing etc. a bit it can be a good one. (quest hero etc.) Maybe also consider setting the value to 0,5 so it does not get out of control too fast.
Summoning is a good place to start mixing things up, I agree some of the summons is very subpar (Igny's and stuff), so any changes there without messing up too much will be okay for most people. I get that you want to balance summons vs evoker path, but buffing later summons is probably better than nerfing the whole evoker path.
Just as a FYI, try commander hero some more, Battle Cry is insane if you give some love to your armies, they can compete with mage heroes with some work. (mages are easier obviously) And remember people play the game differently from you, so anything you think is imba, might not be imba. ^^
