Upgrading supports to max level + max masteries first is a bad mistake.
Support champions can function at lower levels & several of them don't need full masteries a lot of the time.
Damage Dealing champions are what you should always max out first in terms of level + masteries.
Damage Dealing champions will do garbage hits if they are not high level.
I can even prove the above logic with an example:
Lets say I run an Arena team with the following:
- 2 Support heroes -----> Lyssandra + Spirithost
- 2 Damage heroes -----> Tayrel + Skullcrown
The heroes can move in the following order:
Lyssandra (Turn Meter) ---> Spirithost (Increase Attack) ----> Tayrel (Defense Down) ----> Skullcrown (AOE Nuke)
Lets say I make the Supports heroes max level 60 + Full Masteries
Lets say I keep the Damage heroes at level 1 + No Masteries
Try to image the following:
Lyssandra (lvl 60) ---> Spirithost (lvl 60) ----> Tayrel (lvl 1) ----> Skullcrown (lvl 1)
Now the question:
Are you going to win the above fight? No
The heroes who are supposed to kill the enemy team are to low of a level to deal any damage.
The Support heroes despite being maxed out are merely spinning there wheels in an endless circle.
The Enemy with no threat from your team will eventually win.
Now flip the scenario around
Lets say I keep the Supports heroes at level 1 + No Masteries
Lets say I make the Damage heroes max level 60 + Full Masteries
Try to image the following:
Lyssandra (lvl 1) ---> Spirithost (lvl 1) ----> Tayrel (lvl 60) ----> Skullcrown (lvl 60)
Now the question:
Are you going to win the above fight? Yes
The Support heroes at level 1 can still function at that level.
There only job is to go first + do a buff to your team.
They can accomplish all of that at level 1.
And when your Damage Dealers have a turn - They will completely wipe out the enemy team.