Even with Cage and Grind, ball carriers get tagged all the time. "Black Orc blitzes the back cage corner", follows up, he's in contact. Rest of the cage gets tagged up. Maybe I'm doing something wrong with Dwarves, but I see that kind of situation a lot, especially on turn 8 or turn 16. "Ball carrier blitzes off his marker, runs in the score" is a high percentage play. "Someone else could blitz the ball carrier free!", well, someone else isn't always available and mobile. Its a specific scenario but not an uncommon one. Frenzy can get you in trouble there, "Literally any skill you could take other than Frenzy" does not.
So if we're choosing between Frenzy and Tackle, we're talking about defense. Yeah, you have both skills on the starting roster. But the Frenzy players are MA5 and often free to move. The Tackle players are MA4 and very often start in Tackle zones. "But you have so many Tacklers!". Just personal experience here, again maybe I'm doing something wrong, but I've rarely had trouble freeing up a slayer when I needed one, and often had trouble getting a Blocker in the right place at the right time. It's the same reason why Tackle is a popular skill for Dwarf Blitzers. Coaches who haven't played Dwarves much laugh at that, coaches who have just nod. Because the extra movement really does make a difference, as well as the extra agility.
Maybe it depends on the rest of the team ... Do the Blitzers already have Tackle? That might be enough. What else would help on Defense? Strip Ball? Kick?
But even if you're all set with mobile Tacklers (and a ST4, MA6 mobile tackler is so much better), I'd be wary of getting Frenzy. I
like Frenzy, just not on my ball carrier. Fend is underrated and saves you dodges (You're right, Dwarf ball carriers tend to not get hit all that much, but it does happen). Pass opens up options for when things break down, as does Hail Mary Pass (which is definitely
not the optimal choice, but you'll laugh so hard when it works).
Anyway, let us know what you take and how it works out! If you take Frenzy and it ends up being awesome, make sure to post about me being wrong! Won't be the first time and surely won't be the last