Redline:
If you're planning on playing characters for a short campaign or a couple sessions before creating new ones, I'm sure everyone is relatively balanced. Playing characters with any sort of longevity though, Mystic Adepts are the creme ala creme. Casting spells, physad abilities, initiation, enchanted tattoos, 20 Larma a power point, and then throw in some cyber to cover what few bases are actually left and you're pretty much god-like.
With wireless rules, sammies might as well hang up their katana because you'll never compete. Essence caps, availability, and being flat out hacked aren't worth the benefits.
Not in 5e. Adepts start out more powerful than almost every comparable mundane, and only get worse from there. Because you can trade metamagic for PP, an adept can choose which option is cheapest at any given time, so they advance very quickly.
The problem with the increased damage = increased Drain rules is that it encourages overcasting. If I recall correctly, overcasting a stunball at force 10 only increases the drain by 2, while casting at 5 and adding 5 successes raises the drain by 5. It just causes an escalation, and doesn't fix anything.