I have heard that the impact perk does a lot to redress any perceived "imbalance".
Just means you can stun lock enemy, not really exciting. In Skyrim stun is too powerful, shield bash is 100% effective and impact has to be fairly close to that number as well, weapon bashes I believe are also 100% effective on stunning.
"Stunlocking" is a boring way to be effective? That just sounds.... wilfully obstructive to a solution, if you'll excuse my simplistic assessment

It's effective but considering that anybody with a shield or 2 handed weapon can stunlock from level one up where mages can't stun lock until impact (which requires 2 perks, whereas shield bash and 2H have the ability to stun lock from the get go).
Destruction has a lot of useless or underpowered perks in my opinion and never really matches up to Archery or Melee. Destruction can still be powerful but my mage already has the Expert leveled destruction spells at level 25 and all the damage bonus perks, Fire, Ice and Lightning all +50% damage. From level 25 onwards my damage can not increase in other words other then being able to toss out more expert leveled spells... that's all the damage bonus I'll be seeing from now on out... with my previous Paladin character, my damage sky rocketed around level 30~35 when I started actually working on Smithing and Enchanting... to the point where normal single attacks can one hit kill guards while still holding back on the enchantments that I could use...
Destruction users definitely fall behind in later levels since destruction stops getting more powerful after expert and actually becomes more and more inefficient after Apprentice (Firebolt has a base magicka to damage efficiency of 69%, incinerate only has a 33% efficiency since it does ~2.5 times more damage but has about 9 times the magicka cost). If not for -spell cast cost effects, it'd be very difficult to kill anything that had as much HP as you have magicka with incinerate but actually not too difficult with firebolt... yeah... just takes twice as long to get the actual kill.