I don’t understand what you’re saying. It’s literally part of the game. Questing in The Wetlands or Barrens is as much of the game as questing in Zangarmarsh. It’s the same game, just different parts.
By that logic one could argue in the same faith that “I don’t care about raiding I just want the gear.” Which is ludicrously nonsensical. In order to progress in the game you have to play it and partake in the content of the game.
You didn’t give any “pros” of the boost. There are many threads which give many great reasons as to why/how the boost is an overall negative impact on the game. I’ve yet to find a single reason as to why the boost is a good option for the game.
“I don’t want to level” isn’t a good reason for the boost. Nor is “I don’t have the time.” Would the boost increase the number of players in Outlands sooner? Of course it would, but it’s not the only way for that to happen - just go level. You could easily level 2-3 characters to 60 before TBC comes out if you wanted too. If you wouldn’t play the game without the boost, then you shouldn’t be playing the game to begin with honestly. There are many other games out there that are worth playing, Classic wow isn’t fit for everyone these days and that is totally fine.
Check these posts if you want to see some of the negative effects the boost will have. I don’t have the mental fortitude to try and aptly cover it right now.