Quick maffs to compare it to Secondary Encumber+Galvanized Shot:

Hornet Strike/Secondary Surge: (1+2.2)*8 = 25.6. Encumber/GShot: 1+1.2*13=16.6.

In fact, your Surge multiplier only needs to hit 5.19x to reach parity with Encumber/GShot.

Now, there are two big caveats here, of course. The first is that you will need to build for max energy on your frame, which some people won't want to do. The second is that this is an altfire build, which is fine since the primary fire is adequate for killing weak enemies and charging the altfire.

I'll do a quick rundown of my "greatest hits" builds that I've tried so far:

• Banshee: affinity range fullstrip and an extra 3x multiplier on Sonar with Vome Invocation. I just change my rhythm to double-casting Sonar before doing an altfire nuke.
• Mirage: the clones also shoot their own altfire, although it doesn't benefit from Secondary Surge.
• Inaros: the living grouping ability strikes again! Ball 'em up, zap 'em down.
• Yareli: Crit buffs, and a ragdoll grouping ability. Can spam Sea Snares to charge Surge. Natively high energy pool.
• Zephyr: I finally have a use for Airburst Rounds. Not sure what the interaction with tornadoes is, and hard to test because everything is dead immediately.
• Ivara: Natively high energy pool, can set up for a big Navigator shot with just one extra cast beforehand. Haven't tested if it's even possible to exploit Piercing Navigator.
• Harrow: occasional headshots have kept Lasting Covenant rolling on my 155% duration build. The bullet hose effect from Penance is quite nice for using the primary fire too.
• Equinox: book rips off armour, so I can just Maim to my heart's content and run a more defensive Eclipse build.
• Gyre: more power strength! And a bit of armour strip, not that she needs it. Coil Horizon naturally sets up for the altfire. Electric ticks from Cathode Grace can keep Arcane Precision rolling passively.