There are a few failings that I find irritating:-
The inability to represent domain constraints directly. If I have some domain that is used in many coulumns and in many tables, I want to be able to declare that domain, name it, use the name in each of teh plances I want that domain. But I have to use a check constraint to define the domain instead, which means writing a constraint once for each place I use that domain.
The inability to handle general regular expressions, instead of the silly wildcard stuff for strings - and that compounts the domain issue.
All sorts of other things, but as it's an SQL based system I can't really ask for it to support the relational model, can I (eg why isn't there a symmetric difference operator).
Where is support for the latest floating point standard?
Where is support for the error management capabilities of the old floating point tandard that it claims to support?
I could probably go on,and make a longer list, but it wouldn't be useful.
On community comments, I think MS will happily publish them if they point out real issues; they don't seem to do much vetting of community comments, or pay much attention to them. I guess they might take notice and suppress something if it were illegal or thoroughly immoral or just an anti-microsoft rant rather than anything useful. But I've seen some quite idiotic comments that were allowed to stand, and also some quite anti-microsoft ones that raised real issues but in a pretty offensive manner, which suggests they are not excessively sensitive about what we add to their BOL pages.
As a general