1: Solo queue vs party queue.
Introduce new buff, lets call it "Bravery", it will be stackable to 4 and will be given to a whole group by each person who queued solo.
Each stack of Bravery buff will give +10% hp, +7.5% dmg +7.5% healing done.
Example:
premade 4 vs 4 .. no buffs will be given, equal chances to win
premade of 3 people with 1 random (like most groups these days) will have 1 stack of bravery
group of 4 random people queued solo will have 4 stacks of bravery buff.
This should increase the chances of people who queue solo to do anything against 3 man premades.
2. Sprinting.
As it stands now, melee have to spend all of their resources (TP) to sprint while for casters, sprint is just another free ability at no cost.
Make casters spend all their mana to sprint.
Tough? Well, its the how melee classes have it right now.
And add a new skill to restore 50% MP .. on a 300sec cool down, to make it fair