I don't really see any issue with it if it's something that's officially announced. We have a wishlist feature, and maybe folks want to add items that are yet to be released to that list (if they want to pass that list on to friends/family prior to their bday, perhaps).
I understand your concern about incomplete records, but almost all records on VGC are missing box text, rear cover artwork, cart/disk artwork, etc. Personally, when I make records for items that aren't released yet, it's usually because I'm excited about it, have pre-ordered it, and am intending on updating it with more info as soon as I can.