They should buff radar across the board and then make a counter to it. Having a T2 unit that blanks areas of the enemy radar. This could add an interesting element of stealth to the game. By the time it hits T2 anyway the power of early radar isn't disturbed. You have a way to force your enemy to scout you through other means which will possibly be a buff to firefly's and skitters. You can also use it try and sneak troops up into an enemy base. You can balance it by making it cost enough to not be spamable. Give it a energy upkeep so have lots is punishing. Make the radar blocking range fair so its balanced. It could also stop any allied radars from working if they are in the area, so you can't just willy nilly put them everywhere. I think this could add some nice depth to the game. We need more mechanics that add depth to gameplay rather then just tweaking values.
Any radar jammer is still easily overcome by the vision radius of orbital sats... so throwing those around more would be encouraged. You'd need an indicator of where the radar jamming is occurring, though.
I think I prefer the simplicity of no radar jamming units at all, to be honest. I can see the appeal and I vaguely remember TA having stealth/radar jamming units... but I'm not sure if it suits PA.