To early, much to early to even begin thinking about it. ePSXe 1.4.0 was released in June, so it has been just a little over a month since it came out. Typically, there is at least a 3 month (maybe, sometimes, a little longer) gap between releases. So, IMHO, it is not time to even start thinking about the next release, yet.
sincerely,
sx/amiga