Look at CK3; it doesn't have as much stuff as CK2, sure, but it has a hell of a lot of stuff, and a lot of great new stuff. EUV would take less time & effort to recreate EU4 than it took EU4 to create that stuff because the groundwork of research and conception has already been done. The devs would also be able to discard what players didn't like and only keep what they did.
I wouldn't use CK3 as a positive example of what's "good" until its fully released and has had a chance to actually be played by the playerbase. I:R had a lot of people saying it was great all the way up until launch (and a few sycophants saying it was good afterwards) and now can't manage to average 1000 players.
I would definitely prefer it if EU5 would not be balanced around world conquest like EU4 is. I was really happy to get confirmation that the I:R devs have no intention of making world conquests possible in its latest dev diary. I wish the EU devs would take a similar approach and make world conquests essentially impossible.
Almost every limitation I:R has/had on conquest was completely arbitrary, artificial, and ahistorical. These are not things to aspire to, especially given I:R's complete lack of playerbase when compared to every other PDS game in the last decade (except Victoria II, which averages around the same number of players).
I don't even see where EU4 is "balanced" around WC except in a negative way (ie to make WC harder), at least not since the introduction of Absolutism about 3.5 years ago. Nothing that has made WCs "easier" since then has been intentional with most either being bugs (Tokyo exploit, 100+ Absolution overflow, loan overflow) or terrible balance choices explicitly made for other reasons (0% autonomy Trade Companies, Tributaries in edge cases, and shogunate mechanics). The only thing in recent history that helped WCs is the whole hegemony system, but as has been established in the 15 threads about it, they only serve to make (some types of) WCs less tedious, not easier.