As for Trailblazer, I find I disagree with just about every single design statement they made in the free DM's Day product, so I do not think I will ever purchase it.
. And most don't have a ton of spare cash (I know I don't) with which to buy new product. ...There is no doubt that Trailblazer caters to a specific style of play, and attempts to answer a specific set of complaints...

And thus it isn't worth investing the money in the books, and the time in learning the system (and having to figure out which existing 3.5 content is compatible, and which needs to be updated). Basically, it isn't that I feel it is a worse system, just not enough of an improvement to be worth the cost and effort of upgrading.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.