Concerning the yellow cards, I think a lot of people just got the wrong idea about the merchandise we got when we moved for Thiago. Some people seem to think that he is some kind of destroyer CDM who also happen to posses Pirlo-esque passing abilities. This is simply not true.
Thiago is super good at pressing, cutting passing lanes and breaking up the opposition's build-up (this is what the report card said from his time at Bayern). However, what a lot of people forget is to analyze who he was playing with in that Bayern midfield and if we have been able to offer him anything similar. Also, some people understand ''good at pressing and breaking up opposition's build-up'' as we bought another Fabinho.
Defensively, Thiago does most of his job with his pressing and predictions of where the play is headed next and arriving there quickly to dispossess the carrier or simply intercept. This simply won't happen if you throw him alongside Gini and Curtis. Go watch some of his highlights with Munich and you'll understand what I mean. He's always paired up with somebody much better defensively and who will do most of the defensive work in midfield regardless of if Bayern played a 3 or a 2 men midfield. Most of the time it was Kimmich or Goretzka or both. This makes a huge difference in the ground Thiago has to cover and the type of interventions he has to make. Most people underestimate by a long shot the influence a good CDM (from the destroyer POV) has on a game.
Now look at our season. First 3 or 4 games Thiago is given a similar role to the one he played most of his career and is paired with Fabinho (top 3 CDMs in the world IMO) and either Hendo or Gini. Result? Everybody was raving about him and he was fantastic both offensively and defensively. Fast forward to the end of January when he comes back from his injury and Fabinho is stuck at CB, Hendo is out with injuries and then also stuck at CB and he is suddenly asked (out of desperation and lack of options) to be the last man in midfield because neither Gini or Curtis can do it. In those circumstances the pile-up of yellow cards is logical just as is the lack of creativity.
Also, some people seem to think we have like 4 CDMs in that team. The only two players that can qualify as CDMs, in my opinion, are Fabinho and Henderson (can play the role for an extended period of time if Fabinho is out). Gini, Curtis, Milner, Keita and Thiago are all not CDMs. Some of those guys can be dropped into that hole for a half or so depending on the game and what you need from it but they are not CDMs and will get exposed if you drop them in there thinking they will to the leg work and defensive work Fabinho does.