Currently desert at 2/4 pretty much counter wardens 4/6. Already 4/6 warden isnt strong in terms of comps out there, so I I think Desert needs to be adjusted so it doesn't flat out negate wardens class buff. I'd first change the wording from Reduces, to ignore (still doing the same thing, but you'll see why later) 2/4 25%/50% armor ignore and +8/+12 AD to each ally champion (not summons).
I'd buff Wardens slightly by giving them +AD based on 10% of armor. This would up their mid game, and open up some damage routes by stacking armor, however they may still be a weak 6 of class.
Malphite could use some love since he's by far the worst 4 cost, with a random Mountain Element and little damage. Sure his ultimate has a decent stun, but almost all other 4's have larger overall impacts.
Ocean I think should increase its mana incrementally not all in one chunk, its clunky as is and misses a lot of times where you need a little mana earlier.
I'd change it so it champs gain mana each second instead.