If partners lost customers over that, then that's the partner's fault, not 3CX. If that issue is a deal breaker, then 3CX shouldn't have been sold to them in the first place. If it was installed because someone didn't do their due diligence, also not 3CX's fault. I've lost 3CX opportunities which instead became other opportunities because we have other products. There is no 'one size fits all'. 3CX is tremendous in the situations it fits in and they are always adding more features at relatively the same price point. Most are happy to make compromises because of the value of 3CX. Otherwise there's always work arounds with trunk manipulations or 3rd party add-ons or going to another product. Just don't sell 3CX (or anything else for that matter) based on the promise or expectation of a feature materializng.
And I wouldn't say ignored. Certainly slow in responding or implementing, but the roadmap put out says Update 6/7 with a MAYBE for Outbound Caller-ID configuration. No idea why it hasn't been implemented yet. One would think that since we have this capability with the recent e911 changes that all the necessary 'pieces' should be there to do this. But I'm not writing the code so who knows. But the best way to make yourself heard is voting up the ideas section, and I suppose emailing 3CX with details on opportunities lost because of XYZ feature and voting with your dollars in a sense.
But the simple fact of the matter is if/when 3CX releases this, especially after 5 years of asking, I'm pretty certain it will be announced loudly and clearly.