First off, I want to say I like off-base installations, I think they're an interesting and flexible addition to the geoscape gameplay. They could just use a couple of tweaks, IMO.
#1
It is a good strategy to build UFO yards close to bases for defensive reasons. But unfortunately, this makes it more obnoxious trying to access you base from the geoscape, because the UI keeps asking you if you want to look at the base or the close by UFO yard or SAM site, unless your click was exactly on your home base (which from high orbit, it often isn't). The same thing applies to close by SAM sites.
So I think it would be better if the new off-base installations were on a "lower layer" than bases, so that if you clicked in the general area of both, it would open up the base, not the UFO yard, since 9 times out of 10, it's the base you want to access, not an external depot or autonomous defensive structure (both of whose interfaces are not yet implemented anyway).
#2
The other issue is with radar installations-- they're simply too inferior to base radar to really be worth buying and defending. Methinks players are much better off just building a skeleton radar base than a radar installation.
So I'd suggest giving them a serious range buff, even if you need to limit them more in other ways for balancing reasons.