''If the Heavy doesn't have much of a problem in the meta, then why doesn't it get picked more?''
No, the Heavy Splatling does have problems in this meta since close range weapons and Ink Armor are so prevalent. It's not that easy to mow down close rangers with a Splatling, that ''half second'' in a head to head fight is enough for any close range weapon to kill you first.
It doesn't help the Heavy at all that you actually need to learn things about Splatlings (like partial charges timing) to be efficient with it, unlike the Forge Pro or N-Zap that takes much less effort for about the same rewards.
Second, because of how Ink Armor works (it blocks 1 shot, and then it has invulnerability frames as it breaks), it can block 3-4 shots of a Splatling before the other person becomes vulnerable again, so it gives them a big enough window to close the gap to kill you or run away. Then latency and/or lag kicks in, making this situation even worse.
The damage buff to 32 will help against that though since armor will break on the first hit, but the point still stands.
Another reason why Forge Pro is being picked over Heavy Deco, is because the Forge can make more efficient use of their bubbles, because of the Suction Bombs and the fact that it doesn't have to charge up and can start shooting at them immediately after deploying them. It gives them more control and they are more free with their bubbles than the Heavy Deco here.
