About the welcome plugin, I like the overall concept, but it could be confusing. Usually having missed a new person is either because chat is very active and only a few people use chat mods (to scroll) or because there's an amazing lull in activity and by the time the person is noticed, it's too late. If an AFK player "welcomes" a newbie, the newbie may assume the welcomer is active and available to help. They won't realize it was just a plugin doing the talking. If the plugin welcomes a new player on behalf of an active player, that player may be less than thrilled being spoken for. The best implementation of a welcome plugin I've seen was sticking to a simple " is new to the server, please welcome them to !" in a noticeable color.
As for the anti-xray, last I knew, it was somewhat glitchy. At least with option mode 2. The glitch being that sometimes ores would seamingly appear in place of regular stone during regular, non-cheat mining. Mining the mystery ore would result in cobble as usual, so no harm was done with that, but it was a nuisance to players that weren't doing anything wrong.
