i liked ENT a lot on first-run, and still like it a lot. while i wouldn't rank it in the holy trinity if TOS/TNG/DS9, it's held up - aside for the cringeworthy, horrific theme music - much, much better thna VOY has (though i have mellowed on that show quite a bit). i have always thought that much of the criticism leveled at ENT was unfair - they were right on schedule with all the other sequel shows, each trek show took 3 or 4 season to find its own unique style, and ENT was no different. sure, there were a lot of crap episodes in the first few seasons, but you can say that about any post-TOS trek, and season 4 of ENT is nearing TNG/DS9 levels of excellence and was far better than the derivative, technobabble-heavy VOY.
i suspect ENT is coming iut on blu-ray now simply because, as previously mentioned, it requires the least work for blu-ray release, and also to serve as ST "product" to indirectly promote the new jj abrams crapfest.