I don’t think they even need “modern” tanks. Sure, if Abrams and Leopard can make up shortfalls sure without being training/logistics sinks, but they aren’t being held back using T72’s.
F16/F15 I wonder how much they’d change the game because Buk and such can’t be ignored. I think ATACMS should have happened months ago, but I suspect it wouldn’t be as game changing as we think.
Training up real combined arms brigades+ is probably what’s going to be the biggest advantage. Russia can raise manpower but their ability to train to a high standard is questionable so long as you’re training conscripts and equipping them for shit.
Ukraine will continue to shape the battlefield and exploit Russian weaknesses. This war is lost so long as the west simply maintains their current level of support.
AGM-88 HARM can't be ignored either. Buk M3 is a problem for sure, but it's no NASAMS, still a semi active seeker. I expect any Vipers we give Ukraine will be staying low, fast, and packing modern countermeasures and jamming that work. And let's face it, if it comes down to evasion being what can save your ass, better hope it's sitting in a Viper. Pilot training times though, ugh. 3 months is the bare minimum, but Congress set aside money for it back in July (?) so maybe that might yield something yet? I would expect some F-16s, would be surprised if we gave them F-15s. Strikes me as more bird than needed, would mean more support hours and fuel used for sure.
ATACMS, idk, that kind of range difference opens up a lot of targeting opportunities. East Kherson now has plenty of dug in spots that artillery can't reach. Training and combined arms tactics though, the West is doing a great job here and I hope it only increases.