Strike squad without transport in that list = bad idea. I am also not sold on the Interceptors.
One of the biggest strengths of the original list is how it sticks a giant middle finger to most of the anti-power armor weapons you can expect pretty much all other lists to be packing.
By taking 3+ save guys, all those guns now suddenly have the kind of things they were taken primarily to kill.
With the strike squad hoofing it, I am not expecting them to last long enough to have much impact on the game, and would not be drawing enough effective firepower away from your termies to make much of a difference.
Any AP1, AP2 guns will still shoot your termies or dreads as before, but only now any AP3 weapons will suddenly be worth the price your opponents paid for them instead of being wasted against termie armor.
With that in mind, you will need to be hiding your Interceptors most of the game or risk having them blown away pretty quickly if you want to pull the last turn shunt and grab objective trick.
If you really want the interceptors, fine, but take a 5 man termie squad with a psycannon instead of the strike squad or find the extra points to make that strike squad into a purifier squad.
The loss of 5 termies might be worth the extra mobility of interceptors, but loosing another 5 for an extra 10 men GKSS is a bad trade in my view.
With purifiers, at least you would have a unit worth the effort of screening with your termies and shrouded Libby, and more importantly, it is scary enough in CC that many opponents would actually bother to try and target them if you screened them to take some of the pressure off the termie armor.
The 'upgrade' to grand master also seems like a bit of a compromise, mainly taken to make the Interceptors scoring.
With 'nades your termies should do just fine against most opponents. Anything that will give your termies trouble is unlikely to be all that scared of a GM anyways, so it seems you are not getting all that much more bang for your buck considering how much more you are paying for the GM, and especially with the opportunity cost of the ven psyrifle.
If you are going to just take the Interceptors, I would advise against the GM. Just grab objectives with your termies and use the interceptors shunt move to contest enemy held ones at the end.
If you are taking Interceptors and purifiers, the GM might be worth it as 20 scoring troops is dangerously few even if they are in termie armor, but you still might be able to get away without needing the grand strategy and may really appreciate the extra psyrifle.