I'm not so sure this tactic is so easily dismissed. If you run two blocks of Mortek Guard (our best unit overall anyway), in the shape of "L'" that are side by side (with the bottom of the Ls touching each other), with the 2 harvesters towards the center, you can really cover a majority of the board and take two objectives. Something like this:
11111111111111111 2222222222222222
11 22
H 11 22 H
1111 2222
1: Guard block 1
2: Guard block 2
H: Harvesters
Then models you remove will always be in the two clumps near the Harvesters (note that these are not EXACT diagrams), and both will trigger off of both blocks of Guard. Since damage is done one at a time, when you assign the first damage to either unit you simple apply it to the model that is within both 3" Harvester ranges. One dead model = 2 4+ rolls to resurrect one. If you resurrect 1 (or 2...) from this damage, you IMMEDIATELY resurrect the model, place it back on the table within range of both harvesters, THEN move onto the next assigned damage. In theory you won't ever be targeting a model outside of both Harvesters range.
Does this tactic still have downsides to it? Sure, as said its relying on a big point investment in Guard plus 400 points in Harvester support, but this army should be running Guard heavy anyway. But the blocks can separate if the need arises. And of course, if you take out the Harvesters, the combo falters.