Not trying to be rude or anything, but you didnt make the WYSIWYG editor (the tinyMCE team did) you simply implemented it into phpBB, and I'm pretty sure the phpBB team too could have done it in 3 weeks if they wanted to - but software development has abit more to it that "ok lets do this", studying civil engineering you'd know you cant overnight say "i want this building here and lets start tomorrow", you have to ensure the product/building is wanted, has a purpose, doesnt impact the the existing infrastructure, you have sufficent resource to make it happen, etc etc. Remember there are millions of users of phpBB [people who use forums, this is an estimateion but the number IS large], your view is just one of these, so is mine - the views of the majority have to be considered. One issue i had when looking at your board is it took a few seconds to actually load, this isnt a good thing and something you can improve on. With a WYSIWYG editor, some problems are faced, such as dealing with custom BBCode - for it to be truly what you see is what you get, custom BBCodes, both hardcoded (fancy PHP codes) and database (acp) added, and that is what i feel is the biggest issue with this.
Reading through the remained of this thread there is mixed opinions but generally a yes WYSIWYG editor would be good, would keep up to pace with other forum software and *could* improve how its used.
Another issue is the phpBB team is entirely volunteer based, the main development team have only limited time to devote to the project, and thus what they devote it to is important, for example there is no point spending months developing and perfecting a feature if it wont be used.
If you want it included in phpBB, the first step (i think) would be getting it as a phpBB mod and used by many people, that would mean it has no bugs, people want it and people like it. Saying people "hate" you is no reason to ignore it, this is the internet, there will be people that love you and people that hate you, dont let them interefere with what you want to do. You want to make it a mod, make it.