This is a topic that I will never get sick of discussing, as striking, wrestling and grappling as it relates to MMA is possibly my favorite subgenre of MMA to discuss. Similar to wrestling or grappling, I don't feel that pure striking mechanics translate 100% to MMA striking. I feel they need to be optimized and reformatted to accomodate 4 oz gloves, clinches, level changes, and cages. We have seen Olympic wrestlers get taken downn, world champion grapplers get submitted, and world champion strikers get knocked out.
Clean striking technique is oftentimes very effective, but I also feel that there is something to be said about effective sloppy striking. 2 fighters that come to mind whenever I think about this are Derrick Brunson and Carla Esparza -- both fighters have never exactly displayed very technical mechanics in my opinion, but both are prime examples of "effective VS technical" in my opinion. The threat of their takedowns alone provide them with opporunities to land shots that other fighters wouldn't have a chance to land. They are excellent at level changes, whether they're faking a takedown and throwing an overhand, going for a takedown and failing before following up with strikes, or actually getting the takedown.
Then I feel there are fighters that have very technical striking and wrestling but are a bit more refined, such as GSP and Dominick Cruz. With GSP and Crus, their level changes and/or takedown attempts have always been so seemless -- the double leg shots and knee taps would come with such excellent anticipation, while also maintaining fairly clean technique and clean straight punches (more so from GSPa in my opinion).
With this said, I feel we have seen some great results (albeit mixed results) from some high level strikers in MMA. Pereira and Adesanya are 2 great examples whose striking has translated excellently to MMA. Another fighter that I wish gave more of an effort is Gokhan Saki -- sure, he got flatlined by Khalil Rountree and went 1-2 in th e sport (possibly due to the 4 oz gloves), but I feel he showed so much promise against Henrique Da Silva (surprisingly decent takedown defense) and I would have loved to see what he had to offer.
In a nutshell, I have always felt that MMA is a ridiculously complex matrix of skillsets that muddy the waters of pure technical styles, making it difficult to project how athletes from pure combat sports would do in the sport. I do get excited any time we see a high level striker go into the sport though. A lot of times we see them bring new themes to the table that you don't see from seasoned MMA veterans.