I’d say both of these would honestly just make it worse. Allowing it to deal more damage to the enemy General would just give them even more burst potential. The second one in particular would hurt because it could be played when Mag has no board, resulting in a board wipe as well as huge damage for the non-Mag player. The Magmar player could easily outlast the opponent using heals from Earth Sphere, SF or even Ragebinder.
Increasing the mana cost to 5 would be decent enough. That way it costs the same as cards like Enfeeble and Plasma Storm. This would mean they compete for the same slot instead of always having the both in spades you would have to share them out.
As it is you can often have a board wipe as well as playing a minion on top of it. This way it works the same as Plasma Storm and will most likely take up the whole turn.