I think the key points for him are (those that are evident):
- fast transitions (not that different from Mourinho, who also prefers them) – but not by using direct long-balls
- playing the ball from defense – one of the most visible traits, although I very much doubt that our personnel suits this tactics. One of the big reasons behind De Gea's horrible form (although mostly he's responsible for that himself)
- high-energy play – ideally, active pressing as well; this is why the difference between our highs and lows are so drastic, once we can't outrun our opponents, we either play uber-defensively (against big teams), or play shit football. And this is why the COVID break worked so well for us. Pogba & Maguire don't really suit this approach and neither does Matić (although he can do it once a week). Signings of Bruno, James and van de Beck seem to highlight Ole's focus on this component; and this is why Lingard still plays for us as much as he does now.
The most glaring weakness of this approach is that ideally you'd certainly want a higher defensive line as it works very well with those principles... but we don't use it (and thank god that we don't, Maguire & Lindelöf are horrendously exposed already).
Yeah, there are definite similarities between Mourinho and Ole in terms of counter attacking football. Ole wants more running, more pressing, while Mourinho wanted more tactical options.
I guess almost every team is now playing out from the back, but we struggle in getting the ball quickly up the pitch and because our centre backs aren't quick or mobile, they can't really up the tempo. De Gea will need to improve this part of his game because now this seems a requirement.
The high energy bit is something that is needed, but I feel it comes more down to collective responsibility (like not jogging back once we lose possession) and a cohesive tactical plan, which seems to be lacking. Pressing for the sake of pressing is pointless. And as has been mentioned, we don't really have the defense for a high line nor the midfield for aggressive pressing. Relying solely on the forwards to do the pressing is what we've done, and they do it here and there, occasionally forcing an error, but there's always a big gap between our forward line and midfield.
I agree on the biggest weakness to playing progressive football - i.e. the lack of a high line, but it has to be said, not having full backs who are actually good on the ball and clever in their decision making hurts us. And the lack of dynamism in midfield. So, plenty of shortcomings.
But with the average age of the squad so low, this is an opportune time to have proper coaching to implement a clear vision. If there is one.