* Shorter games. 35+ minutes is too long. Should be closer to 25-30 minutes. Increase minion damage and decrease their health. Cut down of some of the animations like the blue hole and the countdown. Decrease the waiting time between rounds by 1 or 2 seconds etc...
* Slight nerf to level 2 units and slight buff to level 3 units. There is currently not enough of an incentive to level up an unit to level 3. The game favours the quantity of units on the board over their quality a bit too much. Some underwhelming origins like Shapeshifter, Knight, Glacial, Elementalist, Wild, Yordle etc... also really need a carry unit to be competitive with other more meta origins and current Tier 3 level 3 units like Poppy for Knight, Volibear or Ashe for Glacial, Veigar for Yordle, Shyvana for Shapeshifter... come a bit short.
* More gold when only 1 item component drops from the first 3 minion stages. There are currently a few possible outcomes with a varying amount of gold and items but the one where you only get 1 item component and 3 gold is significantly worse than the other ones.
* Morellonomicon and Red buff anti healing shuts down too many strategies. Items like Warmogs Armor or Redemption are never going to be good if their effects are constantly reduced by 100%. While it's possible to nerf the champions that use those items too well, I believe it's healthier for the game to nerf the items. Reduce Morellonomicon grevious wounds debuff from 5 seconds to 2-3 seconds. Make Red buff grievous wounds a % chance to hit effect. Nerf grievous wounds from 100% healing reduction to 50% etc.
* Rapid Fire Canon in a similar fashion also shuts down too many strategies like Assassins, Yordles or Phantom Dancer when used on Ranged carries. It's one of the best offensive and defensive item in the game, simultaneously keeping its user safe in a corner and boosting its dps as the unit no longer wastes time moving and his attacks no longer get dodged. Nerf RFC from double range to +1 range. Replace the anti dodge effect for something else, maybe a more melee friendly effect.
* Elise spiderlings should be doing true damage. Currently their attacks are blocked by the knight 2 synergy that is really common through the entire game, making the spiderling more of a detriment than anything else.
* Brand is Tier 4 and should be able to carry. Increase the speed at which his fireball bounces. Increase the minimum range of the bounces so he doesn't waste it casting it on random lone units as much etc...
* MF needs a new AI. I understand you want her positioning to matter and take some skill but it's currently too finicky. She cast her spell in the OPPOSITE direction or OUTSIDE the board 8 times out of 10. It's just stupid. Then adjust her numbers accordingly.