I've always agreed with the statement that the dm is a facilitator not a dictator and I think stopping players from using anything from wotc is tyrannical. you may be dming but its the players game as much as yours.
And, I am sure WOTC loves customers like you.
In my opinion, 90% of the supplements that they released were complete garbage and a waste of trees. As for 8% of the remaining 10 that was not a complete waste, maybe, 10% (at best) of the content was decent.
And, no, when I am running, it is my setting, my game in the sense that I determine which house rules are being used and which supplemental material to allow or disallow.(when three of my players run, it is their game, respectively in this sense).
Now, I will facilitate the players in that they can go where they want and do what they want within the restrictions of the setting and houserules (as long as they are a) not playing evil characters; b) not trying to power game, min/max or plan builds; c) not interested in pure hack and slash).
I'll accomdate non-optimized (read built for powergaming or min/maxing) builds.
If they want to run a bakery, I'll let them.
If they want to go to the homeland of the druid and barbarian and spend an evening, entertaining the clan leaders with the exploits of the druid and barbarian and help them gain status, I will let them.
If they want to go to the knight's homeland to help him restore his name and his House, reclaim his former fiancee set to marry another, and do all this while proving that his fiancee's new husband is a traitor and framed him, I will do it
If they want to drop an adventure, because the barbarian needs to be back home by a specific day and time to take part in an initiation into a secret society of warriors, I will let them. Or the party can decide to stay focused on whatever adventure they have chosen to, currenty, pursue.
If they want to try and fix up the druid with whores, because he is so tightly wound and they believe his virginity and holding out for "true love" to be the reason, I will let them.
However, when I run D&D, I still set the house rules. I still choose the supplemental material being used and even to ignore or alter some of the core material. That WOTC prints it means nothing and just because a player bought something does not entitle its use at the table.
In the above mentioned campaign, for example, the PHB2 Knight will not be used. I have another knight class and a separate supplement for additional material. The druid and barbarian have certain mechanical restrictions/alterations. Tieflings exist, but are NPCs. Warlocks exist as NPCs, but not the Complete Arcane class- as the Thaumaturge from Green Ronin fits the bill for me just fine.