Increasing rune diversity by removing stats
Lack of rune variety isn’t due to their primary stats; it’s because of the rune 2,4,6 piece special effects.
Strength/Hoelbrak, Pack, and Vampirism are the main runes for power or balanced builds (which make up the vast majority of meta builds). Strength/Hoelbrak are used mainly by celestial builds to get more might through procs and extended duration, which offsets the relatively low power values on celestial. Vampirism is used by squishy DPS as an extra and extremely powerful defensive cooldown. The rest use Pack because the raw stats are so strong and the group proc is extremely powerful.
Ignoring stats, pick any other rune set and compare. Would you use it on a power build for the 2,4,6 piece effects? The answer is almost always “no”.
The offending runes or their symbiotic mechanics need adjusted to be on a more level playing field with the rest. For example, Pack should have its 4pc and 6pc swapped and then the precision bonus adjusted down to be representative of a 4pc bonus.