I agree that doing more heat damage to yourself is a little much (maybe 75/50 or so would be better) but that doesn't mean they're unreasonable items.
Remember that the enemy's physical and energy weapons will heat them up as well + zero heat to you. One full turn with physical weapons and a drone is ~75 heat (0 to you). If one of your weapons does 71/75 and the others are more one-sided (reckoning, corrupt light, murmur, nemo, abomination, crimson rapture, magma blast) you're still going to be WAY ahead.
Regarding the two swords, as others have said it really depends on your set up. If you're trying to stay close, the 2-range jumping swords are awesome since they require the enemy to knock you back twice in one turn to get out of range (so if you get them to use shutdown one turn, they can't knock you out of range). For knock-back builds, however, TerrorBlade is great.
So basically, you'd want to do: a) a set up with something like TerrorBlade + Reckoning, which is great vs mechs that need to get close, or something like Heron Mark + Crimson Rapture.
Anyone have final stats on these items?