So as a DC United season ticket holder, I feel I can comment pretty strongly on Rooney, regardless of whether dismissing Eustace is a good, bad, or silly* idea. Safe to say that they're wanting the recruiting advantage he brings them, if nothing else... the famous name does make a real difference outside of the top flight.
Whatever else one might say, Rooney is very, very clearly an excellent coach. As a team, DC developed and displayed competencies that were largely, often totally, absent in the last 15 years.
In the first half of the season, control of the midfield was absolutely superb. There were games where opposing teams simply could not get a ball through the middle third. The squad played a sophisticated, modern possession game and played it well, with a proper sweeper keeper and smart interchanges between defense and midfield. This was a night-and-day change from everything the organization has done since at least 2010. Furthermore, DC maintained their focus on good ball progression despite the presence of Christian Benteke, who may not be a Premier League grade player any more but is an absolute beast of a target man at the level of MLS... they could have just fallen back on hoof-and-hope, but stuck to the better principles.
A few matches into the season, we switched to a back 3 despite not having planned for such formations in the offseason. The defensive line quickly settled in with the change and coordinated well, regardless of which of our six defenders were put into the lineup.
We had a bunch of ppl in and out mid-year, and the team had to change styles as a result, so there was less focus on possession and more on incisive attacking combinations. Again, despite having no recent organizational history of give-and-go, pass-and-move attacking in and around the box, DC rapidly became very effective at creating dangerous chances through intelligent combo play. The teaching effect was obvious and powerful.
Wayne mostly played veterans, but we did rely heavily on two young players, Ted Ku-DiPietro and Donovan Pines. Ku-DiPietro was, I suspect, going to have a strong positive impact regardless of manager, but Pines was a real coaching success story... he's a tall, rangy defender with a ten cent head, and last year he was absolutely scatterbrained, but Rooney got him settled down and contributing consistently.
Being a good manager is more than just coaching, however, and the rest of Rooney's record is a mixed bag.
Tactics: on the one hand, Wayne showed tremendous flexibility, switching between several formations over the course of the year and implementing a significant style change to match the shift in available personnel. When the team's starting goalie (a pure sweeper keeper type, mediocre at shot stopping and handling but top-notch with the ball at his feet) was lost for the season and we had to plug in his backup (the complete opposite, a conservative shot-stopper with meh distribution), Rooney did not insist on staying in a style the keeper couldn't support. However, matching tactics to the opponent and the situation was a real weakness. Near the end of the season, for example, he trotted out a diamond four in three consecutive matches where the resulting personnel matchups did not and could not favor us. There were a few matches where his choices really hurt our chances out of the box.
Motivation and man management: He clearly had the respect of the locker room at all times, but the team had more games where play was on the flat or uninspired side than can be chalked up to "well, you can't be perfectly dialed in every time." It looked to me like players were properly held accountable, with players having to (and being allowed to) earn their minutes and starting roles fluctuating depending on actual performance. We had a mid-year crisis with a prominent player using a racial epithet during a game (at a teammate, no less!), and Rooney navigated that fairly well so far as I can see, except for the irresponsible moment when he sent his assistant to handle a postgame presser where everyone knew hard questions were going to be asked.
Recruitment: DC has poor ownership** and a limp front office, so Rooney was effectively the GM, at least where personnel handling was concerned. We brought in a bunch of players, some good (Benteke, Mateusz Klich from Leeds, Derrick Williams from Blackburn by way of LA, Lewis O'Brien on loan from Forest, Panamanian international Eric Davis), some limited (Victor Palsson, Ruan, Cristian Dajome, the above-mentioned goalies), and some poor (Pedro Santos, Jose Fajardo, the ever-useless Ravel Morrison). In terms of quality, this was a solid enough record, you don't hit the mark with every guy you buy; but there were three problems. First, it was always likely that Wayne would return to the UK sooner rather than later, but we brought in mostly veterans to help him try to win right away, with little thought for what might happen after, so that the team is now built around two guys (Benteke and Klich) in their thirties. Second, MLS is a salary cap league, and the efficiency of dollars spent was quite low. Third, the team's ceiling was limited; Rooney does not seem to have appreciated that he was assembling a team that lacked pace overall and would not have the technical ability to carve open a determined defense, and we ended up having to play perfectly to our strengths to overcome those weaknesses.
I think Rooney would benefit more from serving as an assistant for a couple of years at least, but he's clearly the sort who likes to set a challenge and meet it head-on, so I suppose he'll sink or swim while learning on the job in the Championship. On the whole, I respect the work he did and wish him well; but of course if he goes to work for SHA, naturally it can crash and burn and I won't shed a tear.
* This being SHA, my money is on the latter, however.
** It's the same group, headed by Jason Levein, that owns Swansea, much to Swansea's detriment it would appear.
