Why not? I think he has way more potential to be a quality player than Gomes or Rafinha for example.
I don't know how to put it better in words, but he is starting to remind me of Halilovic, to some extent.
When I watch him closely, he looks as if he is amazing, as if he has tons of talent (mostly because of his movement, some similarity to Barca's Dna, good technique etc).
But as time passes, somehow it seems that he just "looks pleasing to an eye" and more or less nothing happens when he is on a field, plus he lacks in lots of other areas like defending, his positioning can be strange etc, plus he disappears so many times from matches for very long periods of time (you get a feeling that he is invisible both to teammates and opponents).
I am not trying to say that he has mental issues like Halil. No. Denis is normal in his head and has zero problems.
So, he "looks" shinier and better than Raki, Gomes, Arda, Rafinha, Roberto.
There is something in his first touch, technique, some magical passes.
There is something "visually appealing" about his movement and technique.
But when you dig deeper and analyze and watch his play deeper in 20-30 matches and his impact onto results and team's strength (when he is in the team and when he is not), he turns into a very average player compared to our other Cms.
In that sense he reminds me of Halilovic. Visually his movement and style looks "wooow".
But then you put him in a team, more or less nothing happens.
So, he "looks visually shinier" than our other Cms.
But other guys, even though less shiny, offer more impact when they actually play (even though they have weaker technique and less magical passes) but they are just able to impose themselves more and a team looks usually stronger and more compact when other Cms play.
Imo, a starting place in a team like Villareal is limit for his set of skills.
If we need to chose squad players (and who will stay here) out of Rafinha, Roberto and Denis (Arda and Raki will be gone, and Gomes is a strange fit currently), none of them is good enough to be a starter and Rafinha and Roberto have better all-round skills than Denis and seem to fit better into a Cm role in our system.
Even though, everything is possible in life and anyone can improve insanely even in older years, and he is here for only 6 months, he could improve when he learns our system better, but...