I don't really think starting fresh and doing the same things over again is ever really a solution to a problem, but if you do want to go ahead and try, I think this should work.
Before doing it though, if you can install bootmii to boot2, I would highly recommend that you do and make a NAND backup of your current state, verify it works, and back it up to your pc before starting this. Then when you finish doing it successfully, you can make another NAND backup of your relatively virgin state so you can just do a NAND restore of that if you ever happen to need to clear it out again.
Moving on, I think NANDclean or Hack Remover or something along those lines should get rid of preloader hacks on your system
Then run IOS downgrader and cIOS downgrader to make sure you're on 3.2e properly without any CIOSCORP or anything.
Then if preloader still loads, install the system menu wad of your region.
As for the channels you installed, the best way to get rid of them would be if you still had the wad you used to install them. Then you just load that wad in wad manager and have it uninstall it instead.
Otherwise you have to find the ticket of that channel in Anytitle Deleter and delete it using that.
Then I think the only thing you would have left at that point would be whatever cIOS you installed and the HBC, which can be deleted through anytitle deleter by deleting IOS above 200 (mainly just IOS249) and the HAXX ticket for the HBC.
Though there shouldn't really be a problem with keeping those if you want to start fresh.
Just run a cIOS Installer again for whatever rev you want to use to install over whatever one is left, and continue from there.
