This would bring no advantage other than allowing to change your heirlooms if you want to change your class, so I don't see how it will lead to more goldfarming. Not to mention the time it takes to farm 600k gold you might just as well retire 3 times and get 1 more masterwork rather than reforging your current one.
This would also at least partially fix the problem of heirloomed weapons that get nerfed to crap in the latest patch. Trading won't help you with it as nobody will want them obviously.
Your first point is exactly why this idea is kinda lame. Archers and players who like to run around in peasant garments wielding a staff are piling up heaps of gold atm, where most people (including myself) play in about 20k-35k gear making very little money.
I posted somewhere that the average modifier you play with (assuming 50% chance win/loss at all times) is about 1.8 (rounded the number up). That makes a 90 gold average per tick: 6667 ticks to get to 600k gold when playing naked all the time. That's 111 hours ingame, not counting map switches and stuff.
Average multiplier of 1.8 leaves room for about 45k gear worth of equipment to break even in the long term. I play with about 30k gear, so I have 15k "spare room" (the part I make gold with). That's 33%.
That leaves me with 333 hours ingame time I have to play to make 600k gold.
Again, with the 1.8 average multiplier in mind, I make ~61 MILLION exp in the same time it takes to make 600k (I'm gen 8, so 1700*1.8*19980 ticks).
Conclusion:
When playing in my current gear, with my current generation I can make enough exp for 7 retirements in the time it would take me to make 600k gold.
This seems about right, as I've made 50k-60k gold this gen and I'm halfway to level 31.
It would make the reforging a bit redundant imo, as I can create 2 new MW items in the process.
**DISCLAIMER**
I've done the math to my best knowledge, if I've done something wrong you can correct me.
I hope my post made any sense.