First off, I said build and current holes in his game. McAvoy is a much different style of defender than Makar, and has always had a much more well rounded game. The holes in McAvoy's game were never really there. People doubted his ultimate upside in his draft year, but he was a player playing at a pretty high level and controlling the game (his freshman season was damn good, one of the better I'd seen from a draft eligible kid). I was a big tire pumper of his and continue to be. The kid is very good in all facets of the game and always has been. On the build... they are VERY different. McAvoy is a touch over 6' and Makar is a touch shorter than 6', but that is where the similarities end. McAvoy has that pancake frame like Ray Bourque had. He's gonna be a 215-220 lb defender long term. Makar doesn't have that frame and should never put on nearly that much weight. It would hurt what makes him unique.
Any current holes in Makar's game have no relevance on #1D potential, unless you think he won't fix them. Every young D man has holes in their game. Plenty of #1D men had them at his age. The only thing that matters is if he can continue to round out his game.
I think the holes in his game are overblown anyway. One of the biggest things with his game not working as well for UMASS, is that he tries to make plays that his teammates aren't capable of pulling off. He makes passes that more talented teammates could feed off, that miss the mark, or aren't handled well. Personally I don't want him to adjust to his less talented teammates, I want him continuing to make those plays, because a lot of them will work when he's on the ice with MacKinnon, Rantanen, Jost, Landy, Girard, etc.
I'm not sure Makar is a shorter than 6'0" either. There are multiple photos to judge of him standing next to players 6'0" or bigger, and he's just as tall. He's not a lanky 6'0." McAvoy may be a bit more filled out, but it's not a huge difference. Makar is built pretty well. He's already quite strong for his age.
McAvoy was 199 lbs at his draft combine. He's listed at 207 lbs now at 20 years old. Unless he adds fat, him being 215-220lbs seems a little unrealistic. These guys get pretty close to their mature playing weight at around 20 now. Maybe he's under listed though who knows. I'd say 210 lbs is more realistic. About 5 lbs more than what I think Makar will be.
I think Makar will probably end up around 6'0.5" or a tad taller, and easily could end up rounded up to 6'1" in listings. Probably be around 200-205lbs. He's already close to 200lbs at 19.
Not saying he'll be as good as these guys, just pointing out their measurements, in relation to #1 potential. Some of these guys aren't viewed as #1's anymore, but they were at one point, and others had consensus #1 potential.
Drew Doughty - 6'1" 200lbs
Erik Karlsson - 6'0" 191 lbs
Duncan Keith - 6'1" 191 lbs
Roman Josi - 6'1" 201 lbs
Mark Giordano - 6'0" 198 lbs
Marc Edouard Vlassic - 6'1" 205 lbs
P.K. Subban - 6'0" 210 lbs
TJ Brodie - 6'1" 182 lbs
Kris Letting - 6'0" 201 lbs
Charlie McAvoy - 6'0" 207 lbs
Ivan Provorov - 6'1" 201 lbs
For the record, I'm fine with Makar returning to the NCAA, if that's what happens. I think AHL would have been the best route, but I always like defenseman to marinate at lower levels, even the high draft picks.