As the source of your direct quote, I will say it's not that I didn't think of it, it's that I legitimately don't think it's a problem.
Pretty much every solo encounter should be done in seconds so you don't need very many fields. (If it takes longer for you and you're actively thinking about quick uptime, maybe you need to think about one of your two free equipment sets focusing on damage, take it from someone with 21 full map completes) Even then mortar kit has 4 fields on its own that it can drop and no one should realistically be taking the other elites if they're focused on quickness as sneak gyro and elixer do nothing to contribute and crate's cd is far too long to be worth it. Poison gas shell in particular is a 5 second field on a 10 second cooldown which covers 50% of the time on its own. If a player can't work around that let alone all the other fields you'd have access to, it's absolutely pilot error on their part.
In short, assuming we can actually get the finishers to hit the uptime we need. (Which I am still skeptical of) fields are the least of my concern because of the myriad of them engi has access to on a single util skill alone.