DOA5 is going on 5 years old at this point. That's ancient in modern FG terms, and most games with comparable ages have died off outside of Japan. I really would like to see a DOA6 somewhere in a year or so, but given their decision to focus on cosmetic dlc, I don't expect it. There's like 4 majors year round in the USthat have it, and it's basically a gentleman's club of people who still get top 8 from what I see lol.
With that said, Koei Tecmo has handled the game very well imo, and even with the major shifts from how Itagaki wanted the games to be, DOA5 has worked surprisingly well. Probably the most competitive version in the series, and they acted along the FG esport surge well, despite being a fringe title in the genre.
I don't really see a reason to try and play it seriously at this stage though. Nothing wrong with playing it with friends/for fun. For whenever I do get on it now, it feels stale. If a DOA6 ever does come out, I hope they try to balance pushing the competitive/fan service aspect.
The fan service stuff will always be part of the series, and people will always complain. Even when it was DOA2U people complained, and that is hilariously tame compared to DOA5. It's funny when you think of how much fan service SF5 has gone with for its female characters so far, but it's w.e. I would never let that be a reason not to enjoy a FG.