Look at the post total for this thread. It will tell you everything you need to know about the relevancy of this band post-Tilian.
Except not really. When Tilian was in this band, news threads about ToM never cracked 50 replies (and the one about him leaving sits at just 63). When they released a new song last month, that thread got 51 replies.
As for this incarnation of Tides, they have a solid amount of carry-over fans, but their new instrumental songs appeal to a different type of audience. For a website that primarily covers music with heavy focus on lyrics, of course a band that was never big previously isn't going to seem relevant without vocals now. Going instrumental and changing their sound may actually prove more successful for them than ever; the television and motion picture industries could find a lot of use in new Tides of Man music.
If you don't enjoy the band sans Tilian, that's fine. I understand their current direction isn't everyone's cup of tea. There's no need to drag their threads down, though.