I was thinking about more professions on each character, and while that would still be a great move, I want to address the root of the problem.
“Forced” Engineering
I think of a “forced” profession as one which players feel inclined to take on their characters because of some benefit they would otherwise miss, and not because of their enjoyment of the profession.
To me, engineering is such a profession. Because it gives me access to the Engineering Battle Rez, which is critical for anyone who is serious about M+. It has other bonuses in M+, such as the engineering-only calmdown in the Manastorms wing, and belt enchants which stop your tank from taking hits in dangerous moments or grant you invisibility. Not only that, but my characters are required to be engineers if they want access to the loot-a-rang, and more portals across the world(s). Finally, this is less of an issue thanks to the recent auction house mount, but engineering is required to access auctioneers in many capital cities, which is a huge quality of life feature people won’t have if they don’t choose engineering.
People should choose engineering because they want their character to make nifty gadgets, but everyone should still be able to buy and use those gadgets (especially brez) without being an engineer. Everyone should be able to access permanent auction houses in every city. Everyone should be able to move between zones and continents easily.
All my characters are engineers for the reasons mentioned above. I feel like there is only one profession choice because of it.