We don't know, but with a break and possibly new perspectives, MP likely wouldn't have wanted to repeat what they did on those two albums. Let's not also forget, rock and metal has taken a tumble these last 10 years, if you look outside the bubble of these genres. No where near as popular as it was in the 90s/00s. The musical landscape was a lot different in 2015 or so, compared to the late-2000s, so if they came back with MP around 2015, they might have tried different things. MP has stated they always tried not to repeat themselves, or sound similar to the previous album. I have to imagine many of the ideas from the last 4 albums would be on these hypothetical 2010s DT albums with MP, as he was more of the visionary in the band than JP is, as well as the arranger of many of DT's songs. I've always acknowledged that there is gold in the Mangini albums, but it's clear that no one in the band currently are creative song-writers/composers, and lots of the magic in the first 10 albums is because of MP's input, whatever it may have been. This can be verified with the many behind the scenes/making-of vids released by DT and Neal Morse in years past.
I disagree that SC and BC&SL are 'horrible'. They're pretty fun records, and really not much of a step down from the previous few albums. You can tell a little that they seem a little burnt out (MP obviously) and JLB is like a hired gun on Black Clouds, so a break wouldn't have been the worst decision.
I have to disagree big time with the bolded. No matter how much MP has told everyone how big of a composer he is, the main writers for DT have always been JP and KM (at first)/JR (since 99). This is no dig at MP, he's clearly a great
arranger and producer, not mentioning his drumming, but to say there's no creative songwriter in the band and that Mike was responsible for most of the magic in previous albums is a big big big stretch. If you watch any of the making of documentaries that you are refering to, Mike's
musical contributions are almost none, he's there working with stuff other people came up with and he's saying "let's repeat this, go back to this section here, you can double this riff here" and so on. That's what an arranger/producer does (and he's very good at it), but he's in no way capable of handling the bulk of the writing himself for any band, or he would've done it already by now. Every band he's been a part of has had major songriters not named Portnoy (Petrucci, Moore, Rudess, N. Morse, S. Morse, Bumblefoot, Sherinian, Kotzen, the list goes on).
Btw, it's completely fine if you don't like MM era albums, and I'm sorry you can't enjoy them as many people here do (as well as lots of people actually attending the concerts), but you don't have to act like MP was the only good thing to ever happen for this band.
As for the 5 year break thing, it's not even clear what really happened there, as IIRC, he even said that wasn't completely true. What we do know is that he tried to get the A7X gig permanently and gambled with DT for it. It didn't work.