Connolly is easily better than Baertschi. He is actually playing and contributing in the NHL right now. Sven seems to have taken a step back at the pro level, I don't know if that's because he was disgruntled, or it had to do with his injuries or something. But it's definitely a bad sign.
Playing and contributing at the NHL level can be as much a function of the coach and team expectations as the player. If you read some of Burke's quotes about Baertschi, it is obvious that he expected a 3-zone player, something which Baertschi admittedly is not (yet). We've seen Kassian scratched and given limited minutes for the exact same thing, yet this board is filled with scathing assessments of WD for doing so. Tampa seems to give more freedom to players to play a skilled, speed game than Calgary does. So I don't know that it says as much about the underlying players as it does their respective teams.
From a production rate standpoint, Baertschi is right up their with Connolly. 1.78pts/60 for Baertschi, 1.62pts/60 for Connolly. Considering Tampa also has the best GF rate in the league (3.28) compared to Calgary's middling 2.82, I'd suggest Baertschi has done well in the limited opportunities he has had.
Does this mean there aren't issues to remedy? For sure, otherwise he isn't available for a trade. But to flat out say that Connolly is worth 2 seconds while Baertschi isn't worth 1 is just plain wrong.