It wouldn't be that expensive in terms of candy and dust to power up #3 to a decent prestiging level. Powering up at the lower levels is a lot cheaper than at the levels above 20. You have a pretty cool pokemon there, and if you can use it in gyms for the cost of a little candy and dust, I'd say go for it.
GamePress
Legacy Dragonite Use
I have one evolved Dragonite with DB / HB that I powered up as my main attacker, but I also have the following wild caught Dragonites in my stable that I am wondering if they are worthy to power up and put into use? Any input appreciated:
Dragonite No. 1., 1413 CP, HP/AT/DEF (3/3/12) or (2/5/10), Steel Wing / Dragon Claw Dragonite No. 2, 471 CP, HP/AT/DEF (12/11/14) or (11/12/14), Steel Wing / Hyper Beam Dragonite No. 3, 244 CP, HP/AT/DEF (15/0/2) or (15/1/0) or (15/0/1), Dragon Breath / Dragon Claw Dragonite No. 4, 1789 CP, HP/AT/DEF (12/11/14) or (11/12/14), Dragon Breath / Dragon PulseMy first instinct would be to just power up No. 4 a little to have another good attacker. I honestly never got to use a DB/DC Dragonite because the one I have has such a low CP. My impulse reaction would be to power up No. 3 to maybe 1000-1200 CP as a prestiger just so I can use DB/DC but this would likely just be wasteful. Or should I just save up for a new evolved Dragonite with a new moveset?