It is almost a consensus that Ho-Oh has bad moves. However, after running some calculation of neutral-circle-DPS, I have changed my mind. Ho-Oh actually has good moves and can be potentially useful!
First, let me state very clearly that how neutral-circle-DPS is calculated. It assumes no effectiveness, no STAB, and that energy is perfectly used (no waste). Therefore it can evaluate moves independently of specific Pokemon/matchup.
The formula is:
DPS_circle = (DPE_quick + DPE_charge)/(1/EPS_quick + 1/EPS_charge).
Some examples of good move set and their circle DPS:
a. Counter + Dynamic Punch, 19.82
b. Shadow Claw + Shadow Ball, 19.81
c. Fire Spin + Overheat, 20.00
And some examples of "bad" moves:
a. Mud Slap + Earthquake, 16.05
b. Bubble + Water Pulse, 15.08
Now let's get back to Ho-Oh. Ho-Oh has access to Solar Beam, one of the best Charge Move. Extrasensory + Solar Beam yields 19.75 circle DPS, which is almost the same as C/DP! Besides, Ho-Oh has the stats (tho subject to adjustment) to back it up as a supreme generalist to deal with Pokemon that doesn't resist the powerful Solar Beam.
What's really wrong with Ho-Oh is not his moves, but that his typing mismatches with his best move - Solar Beam, which hurts his usefulness. On one hand, he doesn't get STAB from Solar Beam; on the other hand, two of the three types (Water, Rock, and Ground) that Solar Beam is SE into are SE into Ho-Oh himself as well, which kind of like Dragonite fighting another Dragonite.
Solar Beam itself also has some problems. Grass is resisted by seven types, unlike Ghost which is resisted only by two. Such drawback further restricts the use of Ho-Oh as a generalist. Luckily, the current meta is friendly enough for Ho-Oh - aside from Dragonite, and the seldom Muk and Steelix you see in gyms, it can deal with pretty much everything. Fire also helps to resist Dazzling Gleam.
In conclusion, Extrasensory + Solar Beam Ho-Oh is like an enhanced Exeggutor. If you are fine using Exeggutor in sweeping gyms, then you will probably find Ho-Oh suitable in your squad.
As a final remark, Confusion + Solar Beam yields 20.13 circle DPS, the highest of all move Combo I've run. If eggy has Mewtwo's attack he'll be the king.
And as always, any discussion is welcomed.