I just got here today, and I'm currently using LazBro MXL, so anything I say may not apply. All my Median knowledge is years out of date.
Aegipan Treewarden gives the highest attack speed in D2 (2 frame attack animation). It is for on-attack procs. You just load up on every 'on-attack' you can, and spam so many procs that your PC melts. This is my favourite build in classic Laz MXL.
Otherwise, you use Shockwave (Sol rune) bow, Treewarden form, and poison flash to start the chain. Punishers everywhere.
Treewarden is all about O-skills and procs. Using actual treewarden attack skills is lame.
But like I said, I don't know the current mod, I just got here.