My suggestion is to go opensource, put the code up on Github and allow the entire community to give feedback and feature requests that will actually get done. Feature requests and bugs will get assigned a slot and the progress can be tracked.
Opensource would allow you to save tons of money. It's clear SS is struggling with coding a stable platform. Open it up for the community to help. You can retain 1 or 2 coders if you want or just let the open source community do it for free. I dont know how many engineers or coders you have but I can tell you 100% it's not enough or they are not qualified enough or maybe just lacking the passion for this project. With open source we all contribute, features would be added in days, not years, all the issues of this new version could be worked out in a few days. This V is like 4 years old and still not much has been fixed. It's time for a new approach. I know admittedly nothing about coding but I use github for multiple projects and it's been amazing. I really think it could help make ship station the platform that it's meant to be, let it be great, let your baby soar! Every one of us wants ShipStation to succeed, no one is against going with the new version, we just need to make the fixes to make it usable.