Lets see, this Mass-Driver takes up twice the memory of 2 typical breakers, is twice as expensive to install as 2 typical breakers, and breaks subroutines half as efficiently as a typical breaker.

So what do you gain? Almost certainly you will still need all types of breakers in your deck, so you do not save slots. Actually this card probably eats up extra slots because you will be tempted to cheat it out. You are including this card solely for its special ability, but I guess we probably knew that going in. Unfortunately, this card is so inefficient that you are better off just breaking the next ice normally. Furthermore, unless you are Kit, you are counting on the corp to position their ice a certain way. Good luck with that. Finally, there is no guarantee that the ice behind the piece you break has less than four subroutines.

Pro tip, use typical icebreakers instead of Mass-Driver

Dean provides excellent value if you need the strength for more than one ice in a run. But how can you get value from Dean if the corp doesn't put all their sentries in the same server? By using ice that that can break more than one type of course. Most obviously, this means an AI breaker like Overmind, Brahman, or the newly released Mammon. Dean has anti-synergy with the King of AIs, which is probably for the best. Speaking of newly released cards, the smart person breakers can often be used multiple times a run much like an AI breaker. Furthermore, a code gate breaker is often useful multiple times per run with Kit.

Dean can also be a lifesaver in a deck that relies on fixed strength breakers.

3 Thoughts on this card:

1. 3 Credits for 2 Memory and an ability is a good deal.
2. The recurring credit ability pushes Mirror into stealth builds.
3. Getting a recurring credit back is only useful if you can spend it again, encouraging multiple runs.

Indexing, Notoriety or Encore are all in faction and synergize with Mirror. Net Mercur goes with the recurring-credit stealth cards that Mirror needs. You could get rich easily with Temüjin Contract on R&D. We will be seeing this in a lot of Smoke decks, but other options are viable for stealth as well.

This is a runner card that allows the corp to fast advance. Furthermore, the corp benefits from Akshara FIRST because the runner used up their extra click by installing her (barring shenanigans). If the runner is in need of extra clicks, there are less risky ways to get them. Hyperdriver, Stim Dealer, All-nighter, Amped Up, Temple of the Liberated Mind. In other words, Akshara's not going to be competitively played. There could have been some real potential if she was a corp card.

I'd say her best shot at seeing play is in a Jesminder Sareen: Girl Behind the Curtain flavor deck. I'd still include The Price of Freedom when it comes out, for the sake of drama (and cuz Akshara sucks).