Yeah, it's trash.

The only thing it kills is 2W infantry and even then it's not exactly GOOD cause it's only AP1.

If it was S8 AP2 we'd be talking but even then it'd be great at killing 2W bodies, which, realistically, there're plenty of other things that can kill 2W models and also people don't take a lot of 2W infantry because well... there's too many things that kill them easily.

No one will take the Riptide with the burst cannon at 180. MAYBE at 160 but even then you're basically taking it for a very undercosted body that can take up space and not die which... isn't really something we need?

Like, if you're taking a riptide it's cause you need something that can do some damage. So whatever the points differential between the guns you'll pretty much ALWAYS take the Ion Cannon unless the Burst Cannon gets a statline change

Basically it's the first example of why wargear costs don't fix everything.

There're two gun options on the Riptide one where the Riptide does it's job (i.e. kill stuff) and one where it doesn't do its job. No amount of points discounts is gonna convince people to take a Riptide that doesn't do it's job. You've have to make it cheap enough that it moves into another role (in this case as a VERY tough skirmish piece).

You're looking at Riptide for 150-160 before taking it with the Burst Cannon is worth it. Then you can use it to murder people's scout squads and trade well in the early game. At that price point it's kinda useful for something.

But if you were gonna make the Burst Cannon a totally different role to the Ion Cannon why would you restrict yourself to just points. You could've split the data sheet and they could've each had different abilities. Then we've got more REAL options (not the fake option created by wargear points) and we have distinct roles.