I think these points are not anything to be too worried about at this point.
Contact: I don't think it's overly surprising for Martin's strikeout rate to increase being thrust straight into AA. He's more than held his own at AA as a 22 year old and think his offensive profile as an OBP machine has not changed. Let's get more of a minor league sample size without the injury before we worry too much here.
Impacting the Baseball: This to me will be something to keep an eye on, but I think it's still too limited of a sample size (including the hand injury), to overly speculate with. If he can get to Starling Marte level power then he will be a very helpful player. His college exit velos were excellent, and there's no reason one year away should change that perception too much. Keith Law mentioned that his swing with the injury has caused more of an inside out swing, which naturally would create less power. Let's see where things go once the hand injury heals in the offseason.
Defense: I think we have a tendency to over analyze defense on these forums to the point where we begin playing a player who can't hit just for the sake of SS defense. I think Martin has a lot of utility (like Arraez) to have defensive flexibility at CF/2B/3B/LF. He does not profile well as a corner outfielder, but would still be a great addition for days where Kepler/Larnach need a day off. Polanco and Arraez will probably be in the ballpark of 3+ WAR players for the forseeable future, but leveraging where they play with Martin could create an incredible top of the lineup. Even if we re-sign Buxton, we know he will miss time so this is a nice player to have who can be a 2-3 WAR swiss army knife who may be a slightly better version of Arraez.
In my opinion, Martin (like Arraez) fits a huge need for the future offense in having table setters for our power hitters. The 2020 and 2021 Twins have had issues with having to out-homer there competition, which to me is not good baseball. I think Arraez, Polanco, and Martin will be excellent future compliments to the way Falvine wants to build out the middle of the order, and I don't think these shortcomings listed by scouts are anything to be too worried about at this stage.