I'd get a new, larger frame for ISO 622 (aka 700c) wheels. It'll be more prevalent in more countries to get parts, and you won't be asking questions why your bike looks too darn small on everything. The old components -mostly- should transfer onto the new frame if that's what you want to do. The exceptions might be things like bottom bracket, headset, etc. Seat post diameter might be different so that may change as well.
But $700 USD equivalent for Sora doesn't seems like a lot of dough. I hope this is a mil-spec road bike in your size at the PX where you get the other "lampshades", right? LOL! And with your mil-creds, you'd figure they'd have 1-hr shipping at Mach 9.3 in one of those new stealth birds with the new hypersonic propulsion systems, and the Quizno's sandwich that goes with the new bike will still be warm and toasty. But typically, outside the US, the cost of a Synapse Sora is going to run around $1000 USD, so your price isn't bad.
And while many younger riders do like to scrunch up in the drops, I've never liked doing that. I like riding the hoods most of the time. And for that, the Sora brifters are ideal and seem to have a good track record for durability and performance. I am somewhat of a retrogrouch, leaning towards old-school stuff like friction bar-con shifters and old steel frames. But I must admit that I am impressed by the incremental improvements in all lines of components from Shimano, SRAM, Campy and others over the years. Even the lowest end components today, shift and ride as good as some of the best back in the day and while I've read about durability issues with components, I haven't personally observed any myself because, just as in the old days, I continually maintain my gear, so I rarely suffer catastrophic component failures. But what impresses me most about new components, are the parts are designed AND PRICED to be field replaceable. Not exactly the ideal philosophy for reduce-reuse-recycle, but for durable goods that you only need to replace every few years, it's not a bad model. I can find replacement parts that are compatible and shift great starting at $18 online (in the US). Can't vouch for overseas. But when you're a big clyde and ride, you need to think about replacing parts under stress every few years or every 10k miles (e.g. pedals, seat posts, handlebars, stems). That Synapse Sora isn't a bad choice at all. And I think you'll enjoy it even more than your CAD3.