I think You miss the point. Mysticism gives you THREE feats that you need anyway. If you want you can get the same feats that Reach would give You. It all comes to choosing if you want more:
a) better Sound Burst + Smite + Magic Stone
b) better Bless + Bane + Prayer + Greater Prayer - at move speed and +2 concetration.
Which is better, as the previous discussion proved, can be disputed.
The 3x extended range feats are irrelevant in this calculation. The choice is not about feats here because 3=3, duh.
I still find weird the need of having all 3 extended range feats though. So many useful feats that can't be replicated by good positioning and so few feat picks - especially on Archmage.
Looking at it closer I see what you mean, but reach still gives you additional benefits besides those feats with enhanced to hit on magic stone which is a great spell that requires good to hit to make use of and reach automatically turns sound burst and smite from close to medium and medium to long as well as increasing their radius of effect. 10 to 1 half dozen to the other.
EDIT: My playstyle makes me lean towards having max range on every caster, I want to control as much of the battlefield as I possibly can.