It won't make it useless. It just giving Ostheer an option to spam trash info to the "Maphacker", if the Soviet player is experienced enough, he will know which one is the true order, according to his army combination and Ostheer unit combination, but not brainless like now, OH SHIT, he got 251, I need to get AT nade and plant some mine at once.
Your suggestion to add trash info would just make the ability the same as basic game sense. I know if an Ost goes T2 chances are hes getting pgrens or a halftrack, if he can spam false info and it tells me:
Ostheer player building: 251
Ostheer player building: Pgren
I'm exactly in the same position as I was before if I didn't have the ability at all.
The only useful info that radio intercept would give me is when the German techs up tiers, which is slightly useful, but would take over tank traps spot as the least worthwhile ability.
And it would make the ability a noob trap, those who didn't know about the possibility to spam fake orders would be a distinct disadvantage to those that do. Or noobs that use the ability and don't realize they are getting fake orders would be equally as fucked.