@Theonas Could it not be argued that Mourinho left a very good foundation at Chelsea first time round? And in fact his work there allowed for continuity regardless of manager.
Grant came in and got to a Cl final and took the title race to the final day. Scolari came in and although his record wasn't as good as Grants, Chelsea still remained competitive and under Hiddink won the Fa Cup and got to the Cl semi finals.
Now that's three managers who at the highest club level have pretty much atrocious or non existinant records.
The Chelsea team and playing style remained predominantly the same during that period. Ancelotti came in and they were Champions again.
After that though is where I think they lost the plot, the desire to replicate Barca football, signing players who previously wouldn't really fit the bill of the successful 2004-2010 sides, acquiring interim managers. This is where it got random, funny though because they still went and won the Champions League, which was a total travesty fwiw.
But yeah I think the Mourinho way worked for them and that's pretty much what they went back to in 2013, last season is unexplainable but now with Conte I see a similarity, favouring strong, athletic and dedicated players. Prioritising solid defending first, happy to play without the ball. It might be basic as you said but it's still an identity and if implemented properly with the right players can be successful.
As far as the situation of us playing players out of position under Lvg , whilst I agree other big clubs do it, they tend to do it in fluid set ups where you're allowed to be creative and interchange positions. Under Lvg we were playing several players out of position in a ridiculously rigid set up where Lvg wanted players sticking to their zones and not taking too many risks. It was completely unworkable and basically led to the worse football we're ever likely to bare witness to as United fans.