The turrets are useful only in the midgame tbh. Early game, unscaled and with no perk points in, they are easily avoidable; Late game - they are a pushover nobody cares about.
If you think McG's ultimate is "balanced", I don't want any of the stuff you're smoking. Where almost every ultimate in the game in the game strikes fear and forces the enemy to play around it, McG's ulti does the opposite and rewards the opponent to go in - the exact opposite it's even supposed to accomplish in terms of her kit. Even if you invest into it heavily it's still massively underwhelming, if not - it's absolute dogshit.
It's literally a button to farm hard camps.