Current generation stock 690 in mode 1 is sleepy, and that might be what you rode Relax. Mode 2 stock isn't that much better but its more responsive and lets you slide a little. With some tuning, the engine becomes an on-off switch in the best way, crank it from any throttle position and it responds fast. The euro 5/5+ tuning really kills the power band in the mid range which is probably where the comments come from. Either wring its neck, or change the fueling.
There's other reasons too. The suspension in stock settings is very soft so the squatting doesn't help the butt feel on acceleration. The TC also interferes no matter which mode you are in so you have to turn it off to let the engine do it's thing. The bike is so wheelie prone that the anti wheelie power cut happens with any slight provocation of the throttle that you never really feel the real power at the top unless you gradually make your way there (or let TC do it for you).
390 SMCR is the same weight as the 690 SMCR. The price tag is the real point of it. It's an updated DRZ released before the DR-Z4S with all the modern accoutrements. This isn't a purpose built machine either so don't start comparing it to a Husaberg or even KTM's own EXC lineup.
Aftermarket support for power is all pre-existing 390 stuff which is a good cheap starting point for supermoto platform. If anything, this is going to be a frontrunner when talking new from dealer, low cost, 'low' maintenance supermoto on the market. Only problem will be convincing people that supermoto is fun again (its not much fun on Ontario roads and highways).