Considering there is an increasing number of lgbt centric anime/manga that aren't just shounen ai or shoujo ai, I think there should be an lgbt category. For example: Blue period, Blue Flag, Our Dreams at Dusk, and Boys Run the Riot are all modern manga that don't really fit in the existing lgbt tags (shounen ai/shoujo ai). There are also older manga such as stop! hibari-kun!!, Claudine, and Wandering Son that probably shouldn't just fit under gender bender (considering they portray transgender people, not traps or crossdressing). Also, most older BL were actually considered and called shoujo at the time, such as banana fish. They do not fit any modern bl tropes (such as uke/seme) and I don't think should be retroactively considered shounen ai. But, neither should they only exist in the shoujo category as they are still very different from your average, especially modern, shoujo. TLDR; The current shounen ai/shoujo ai and gender bender tags are fine, I just feel like they don't fit a certain section of manga, and there are more manga being written with lgbt themes that don't fit the existing tags. I think it would be great to make it easier to browse these manga.