I'm confused at what you're stating Rudra. Yes, the AI pathing is terrible, which is the cause of most of their lagging behind issues. Fixing AI is crazy hard, adding more movement speed to compensate for dumb AI, crazy easy. While it doesn't fix the underlying issues you outlined, I think it would compensate for it sufficiently without adding any "game breaking" elements. Also, I noticed they seem to path better in general when they move faster. Almost like they second guess themselves less once they calculate they are making progress...don't seem to turn around / get stuck / etc. as often.
Also, for reference a 50+1 MM pets running speed:
zombies = 28.92 mph
grave knights = 28.96 mph
lich = 28.99 mph
genin = 50.39 mph
jounin = 50.44 mph
oni = 50.47 mph
(ninja's get slightly faster run speeds from their train ninja and kuji-in zen abilities)
punk = 28.92 mph
enforcer = 28.96 mph
bruiser = 28.99 mph
battle drone = 28.92 mph
protector bot = 28.96 mph
assault bot = 28.99 mph
demonling = 28.92 mph
demon = 28.96 mph
prince = 28.99 mph
I don't have a 50 beast MM, but my lvl 41 beast has:
wolves = 39.26 mph
lioness = 39.30 mph
dire wolf = 39.35 mph
I don't like the merc power set, so I do not have one.
A 50+1 Kinetics MM speed boost adds 25.06 mph unslotted.
A 50+1 Mastermind base run speed is 14.32 mph
swift (1 slot) adds 7.04 mph
sprint (1 slot) adds 17.22 mph
Taking us to 38.58 mph
Athletic or ninja run adds an additional 20.05 mph, moving us to 58.63 mph
Since Ninja's have Ninja run, I think that's a neat unique feature and one that should stay special to Ninja's only. This would allow them to maintain their inherently faster speed.
Allowing swift and sprint to effect pets would only add 24.26 mph, or basically a speed boost, but at the cost of having it toggled on.