weakening the effect of flamers on cyborgs would just make it much harder than it already is to destroy or counter them. One of the main reasons players use flamers are to counter cyborgs.
Effective only in some directions. And as i already proposed, not against EM (only if EM is supposed to be electromagnetic radiation with enough short wave length to be blocked by such shield). And any damage should be blocked only under certain angles.
- With another feature, when harder unit - at least tank breaks order by own hull this may be not a problem.
- Incendiary weapon should easily solve this situation, though shield carrier still could defend self at least from direct contact with flame either by targeting bomber or (against artillery) in order of CB defence (of course, not only incendiary).
In short, such shield may give at least some chance, but not too much. Yet for some better balance too hard hit to shield (with heavy cannon or artillery) should termporarily disable it due to compensation by hand.
This is force field. As for it, additionaly it could be penetratable for flamer, since flame there is supposed to be gas based. Or at least be less effective. But very effective against plasmite

(though some heat, could reach target by air and slightly colded gas, which is neutralized plasma)
And yet about diversion. I don't think, that it is necessary to have special unit type for that, since installation of package to structure is more a build process, and trucks could do it by upgrading enemy structure. One possible restriction:
- Packages should detonate only when truck reaches some distance from mined structure. Or (not sure in what way) start timer (5..10 sec). In this way it could install multiple packages at once. Of course, if enemy trucks don't remove them parallely

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Those, who sacrifice culture for bit of freedom don't diserve any.