I some what agree, but Assuming a crew is "MIND WIPED" (50% proficiency) as they get in a NEW Tank silly. Why wouldn't they remember what Tank they were previously in?
(why wouldn't you want a 5 skill crew in your T1 Cunningham? ) It'd provide INSPIRATION (Tears/Bottom Hurt maybe? ) to those unfortunate Beginners. 
I assume Most players would Retrain their Crews as they go up the line, rather than use effectively "Stunned" crews for the next 50 odd matches until they reach 100% and regain their senses. Players would STILL use Gold for the Trained Advantage in a NEW Tank wouldn't they?
Maybe WOT could introduce "Premium Crews" to fit ANY tank that are limited to maybe 3 Skills (Perhaps "X" Gold per Skill? ), and Gain NO crew Experience but instead Bonus Vehicle XP to help with grinds?
(I know Personal Reserves can in effect do the same thing, but the Few Personal reserves I've used seem to actually be "Personal Curses" and seem to set RNGesus and MM on a Personal Vendetta against me. )
In a related Crew Question, those Crew who are Multi Station (Commander/Radio or Commander Gunner etc.....) skilled, say the Commander has "Jack of all Trades" Perk, and is Multi positionaly skilled, does this give ANY Bonus when say a Gunner is Taken out, "Jack of all Trades" kicks in, and the Commander who is also a Trained Gunner takes over?
I should have a look at Potentially how MANY positions a Single crew member can be trained for? "Swiss Army Crew"