Do you really need anyone other than Loomis appear on cd?
this.
I believe Loomis does just fine on his own. Loomis writes the majority of the music even with a second guitarist. Smyth only had writing credits for 3 out of 11 songs on This Godless Endeavor, and on Politics of Ecstasy it doesn't really specify writing credits but I'm sure it was still a majority Loomis on the music writing.
Its good to get a secondary opinion on music, but if it isn't broken who cares?