I'd imagine the Soviets tried to borrow similar ideas from the F-15E. But they likely lost interest since they had
other progs like Su-27IB (later Su-34) underway.
Otoh, the Su-27UB variant, which the Su-30 model evolved from, was originally only meant to be a 2 seat type trainer.
The Soviets already had a history of making a strike jet from an ASF, like Mig-23 and Mig-27, before the F-15. Or even the Mig-21K, but it lost to the Su-25.
There are two distinct families of the Su-30. Both derived from Su-27UB, which later became Su-27PU. The PU was modernized into an ASF called Su-30MK by Irkut. From there, Irkut created the Su-30MKI family as an ASF and KNAAPO created the Su-30MKK for ground strike.
KNAAPO made an ASF version called Su-35UB, but the Chinese rejected it 'cause India had the same version from Irkut (canards, TVC, Bars radar etc).
Imo, if EWP were viable, we'd have seen them on just about every 4G/4.5G combat ac by now.
Yeah. It's not worth the effort compared to the real deal. Every time an option came up, it was to displace a more advanced jet. Like the Su-47/Mig-1.44 in SU and F/A-XX and F-47 in the US.
Rafale was supposed to get it, but their stealth tech took care of that.
One of the biggest dangers of the pod is you end up carrying too much weight and it's difficult to get rid of during emergencies. And you have to lug them around even in dog fights against a clean enemy if you intend to save them. It puts pilots in a ridiculous position. And all for a minimal reduction in RCS.