Of the 2 remainders, fel is the better of the 2 as it scales into the late game. The bonusses it provides, even though small, do work.
Convection only boosts the very early game, which requires hits, while enemies can relatively easily dodge this. Making it that far niche, that it only works when the enemy just didnt draft well enough (or QM).
However, if enemies are doing decent drafts, the moment you show a mage, they are also going to look for ways to blow up a mage instantly. This makes the passive healing not do a lot. So it only is about 4% spell power, which is the value of 1 level in diffirence. Quite minimal.
Its a talent that only works when you lack a healer, as it at least covers that aspect, which makes it viable for QM.
Thats why in draft games people go for the shield and max mana. Its because it works in nearly all cases where you would draft kael anyway. And isnt realy something that can be countered (zoning the globes can be done, but kaels teammates can still grab them. But its the hardest part to counter him).
That tier does have issues, and thats because the shield itself is extremely powerful. The other talents just do not scale to equal levels. But at the same time, i wouldnt be surprised if the main reason for kael winning is mostly down to how well the enemies can avoid kaels bomb.
But how to solve it, i dont have any idea, since in its basics, it does provide decent variety which they shouldnt destroy either.