I admit, when I first saw this thread I immediately went "Nooooooo D:" xD Because while in most cases I'll take Yulyhn's linearts over Equimagine's,
nothing can top the adorableness of Equi's PPS lines, and I really love her unicorns too.
But after thinking it over and reading a lot of the replies here, I voted "Yes". Of the 5 examples Tess posted, I find 4 of them to be a genuine improvement. I like those odds. And the new draft horse lines are beautiful! I'm a huge draft horse fan, but I was never that into Equimagine's drafts because they were a bit too cartoony for me. The new ones are so much more realistic and pretty... I could definitely see those becoming one of my favorite species on the site.
Plus, this would have the added benefit of making horse items accessible to all horses, and it would get rid of the art theft controversy, which are both positive things and good for the site.
Also, and I'm not trying to start an argument or offend anyone... but if Equimagine pets are as well-liked as people on this thread are saying, why are they so darn difficult to trade?

I used to hoard them, but as time went on I grew tired of my hoard and kept one of each horse and pony but put all the extras in a doubles group that I will happily trade out of. There are 285 pets in that group, and a good half of those are the old, old Equimagine lines, but do you know how rare it is for me to actually trade a pet out of there? Nobody ever offers on them, and finding people who will actually trade me anything for them is incredibly difficult. And when I do find someone who will give me a rare dog or two for horses, I usually end up massively overpaying because the demand for them is so low. If I had an easy time trading them, I would probably vote "No", but I feel like a lot of people are voting "No" more for nostalgia then because they seriously love and collect Equimagine horses, and for that reason I'd rather see them revamped and possibly get a slight increase in demand.