I think ETH has all the tools to be a success at United, given some certain conditions. Conditions like will he adapt to a new culture/land, will he survive media scrutiny (yes, he will be scrutinized for the way he talks/acts) and will he be given time by the board, if he's not off to a flying start.
Here's my three reasons why I think he will succeed:
Opponent analysis and game tactics
The way ETH seems to know his every opponent and prepare his team is unlike something I've ever seen before. He is SO good tactically. He allowed us to be so dominant over the last 4,5 years, in the domestic league, but also in a lot of CL matches. The way he prepares his team for the match is often superb. point of improvement is his in-game changes in tactics/subs. Subs seem to come late often, and he doesn't mix up his tactics too often, if his initial game plan is not working
Player motivation/discipline
Whilst ETH is not the most charismatic of managers and doesn't strike me as a particularly good people manager, the discpline has been at its highest it's been in many years. This is particularly impressive, as Ajax has invested heavily in players over the last years, meaning wehad a full/bloated squad with a lot of good players on the bench. This was always a recepy for disaster in earlier years, with a lot of divide within the group, leaks to the press, etc. But none of this has happened under Ten Hag. I think it has something to do with the fact the he is so demanding, of himself and of his players, that the players recognize they simply cannot feck around with him. He can be pretty ruthless in that sense, if you're not with him and his way of working, you're out. Simple as that. Also the in-game motivation and discipline has been very good, the players really seem to give it their all. I think this is where he will add most to United. To me, the biggest problem you guys seem to have is within the mentality/discipline/motivation domain, and Ten Hag will really shake it up. It will be a shock to most, but I think most will be able to adapt. I guess the players don't
like to be as unmotivated as they seem at the time, but it is just a consequence of years and years of neglect and bad management in this area. This seems to have created an environment where underperformance is the standard for most players. ETH will definitely shake things up.
Attractiveness/style of play
Simple. We score tonnes of goals, play dominant football and the matches are good to watch. This won't automatically bring success, but at least the matches will be better to watch in the process of achieving success. To me, this year we suffered somewhat in this area. You get a really strong
fin du ciecle vibe with this team, where our best players are aging (Tadic, Blind) running down their contracts (Onana, Mazraoui) or leaving for sure (Gravenberch) and some of the other players are simply not good enough (Alvarez, Klaassen). In that sense, I think it is a good thing we are gonna get a big overhaul this summer and shake things up a little bit. ETH has gotten the most out of Ajax that he could, and now it is time for somebody else to pick up the glove, preferably with big changes in player staff as well.
Looking forward to watching ETH coach United next season. Maybe
@BrilliantOrange can elaborate a little more, as he is more knowledgable on the tactical side of the game.