I definitely agree with this. Even Dreadwyrm Trance was a direct copy of Demonology Warlock's Metamorphosis ability. Of course that now belongs to Demon Hunter, but nevertheless. Though basing the job off Warlock is not inherently a bad thing. SE has just done a bad job off it in some areas.
Honestly I don't think the issue lies with specific job based mechanics. But rather the game play mechanics as a whole. FF14 has the most linear and rudimentary game play I have ever seen in any MMO ever. It's almost like the FF13 of MMO's in terms of how linear the game play is. Which I personally think is very foolish of the devs. The word linear should never be used to describe any part of an MMO. Yet almost everything about FF14 is linear (apart from the actual environment zones). Everyone who plays a certain job will just be a proverbial "copy/paste" of another person who plays the same job. That is because there will only ever be one rotation to do, with the same abilities to do. One gear set to get, one weapon to get. One way to meld. There is no room for customization or trying new things out. As a result any and all jobs will always lack depth. Which is the real reason why SMN still only has 3 Egi and has to get the rest via glamours. There is no room for new pet types. There is no room for an elemental wheel. There is no room for anything beyond the baseline, rudimentary system we have. Which is what's forcing SMN into this corner in the first place.
It's not SMN that needs an overhaul. It's the entire combat based game play (job progression, skill progression, gear progression, etc) that needs an overhaul.