B/DP Gyarados - a legacy worth forgetting?

I have a few DP Gyaradoses, along with a few DP Laprases. I guess for me, the answer is that they might change the move damage output and energy requirements, like they did when gen 2 was released. Everyone who had transferred confusion Exeggutors or body slam Snorlaxes regretted it, as did people who transferred their aqua tail Vaporeons in favor of water pulse Vapes.

That said, I live in a very karp-heavy biome (I catch enough at my house to evolve a Gary about once every 3-4 weeks), so I have enough Garys with the better movesets anyway.

The difference between DP and outrage is really not that great (though outrage is clearly better), so I certainly wouldn't TM it in the hope of getting outrage.

Make it dragon tail/dragon pulse. Could be a pretty cool, unique mon.

I'm keeping one with DP, but I also have ten Gyardos now. I TM'ed my Dragon Pulse Dragonite because I didn't have one with Hurricane yet. I am a little worried that DP could make a comeback when they tweak the moves again, but I had a need for the mon now.

Be careful about TMing away legacy. DP smells like it could become valuable in the future. But that's just my hunch.

As alternatives for FB Mewtwo, consider Dragonite and bug Scizor.

In answer to your question, yes TM it. (unless you like collecting legacy pokemon.) Dragon pulse will never at any time match Hydro Pump on Gyrados.

If you want a dragon counter, just use Articuno ;)

I had a Gyarados with B/Dp and two with B/O. I TM'd the Dragon Pulse into Crunch to use against Lugia, and prepare for later against Mewtwo. Possibly a mistake, but Outrage is better now and I use those two a lot and had not even used the one with Dragon Pulse in several months.

On the other hand, I have two Dragonites with Dragon Pulse that I don't want to risk changing and getting Hyper Beam.

i tm'd my high level 100%
I want to use to use it for something most likely double dark for back up against focus blast mewtwo.
who knows if DP will ever become relevant
who knows if anyone will still be playing by then.
with the inevitable power creep who knows if gyrados will ever be relevant again outside of very narrow usage.
So now is the most improtant

I kept the Twister one :) (also changing bite to DT) and TMed to Crouch the DP one.
Granted that Twister one is mediocre IV lvl 30 while the other one is 98 IV 37.5 and aimed towards MewTwo.
Play with an eye in the future but the other eye and the rest of the senses in present.

Charge TM it, at your level you almost sure don't have the dust and candies to build 4 more powerful MewTwo counters (5th being your other Gya).

If DP gets a buff I will consider powering up my DB/DP Gyarados, he is lightweight but can pack a punch (I just wanna share my legacy movesets and tiny Gyarados :D)