Honestly the Bubbler may very well be the worst special on this thing. It's clunky and awkward just as you say.
Which I suppose may be a balancing move, since the Point Sensor is so strong on this thing.
I don't really agree with this. It's benefitial for a Bubbler user to have range, since even if you're being pushed around you can almost always still reach you're opponent, often resulting in a splat. (For instance, the Bubbler doesn't really match with Inkbrush in the Nouveau set since you can be pushed around like a pinball, with them very easily outranging you, forcing you to back up because of something that seemed to be your advantage.)
As the Classic Squiffer can be used quite supportively with the Point Sensor, the Bubbler adds to this idea since since it can initiate a big advantage state for your team if multiple members get it.
When used offensively, you can throw a Point Sensor or two first to mark your opponents before activating the Bubbler, since your ink tank is instantly refilled. This allows for the actual splatting to be easier, too. (Though i can't see why this wouldn't be useful to do defencively, either, if you happen to have the time to throw the Point Sensors.) If you have teammates with you, the situation becomes incredibly advantegous for your team, with the opponents often being marked and you having multiple members able to run rampant with the Bubbler. Even if you don't get anyone splatted, you almost surely will capture the area, which can be crucial in any game mode, but especially in Splat Zones.
And of course, the Bubbler helps defencively with both surprising situations and planned defence. The Bubbler is especially useful for the Squiffer in situations where a weapon with shorter range tries to assassinate you, with the opponent being in your face, since the Squiffer normally has a hard time that up close. And for planned defence the Bubbler is marvellous because it can completely stop the opponent from advancing towards the objective for a few seconds, which can often decide the whole match.
It's true that, for instance, the Kraken, beats the Bubbler in mobility and solo offence, but the Bubbler, imo, is stronger with teammates for offence, and has much better defencive capabilites than the Kraken overall(since you still retain your range and you can spread out with your team of bubbler holders). Also, you can also use the Bubbler to rush in to a Splat Zone to fill it with your own ink, possibly netting you the counter, or at least disrupting the opponents'; this has won me some matches. At least, I don't think that the Bubbler is the worst special for the Classic Squiffer. I'm not even sure if I'd main the weapon had it Inkstrike.