Here are a few things I think are needed features in Shipstation
Need to be able to bundle different sku's together. Some of my products come in bundles and it messes with my inventory because I can't bundle it to automatically take it out of my current stock.
You need to allocate orders for the inventory to show what products are "committed". It would be a lot better if inventory just showed what was already committed without the need to allocate. Or at least give the option for one or the other. This way I could just see what stock I'm negative in.
There is no sorting feature for what is most important in the inventory section: On hand, available, or allocated. Should allow more options as to how to be able to view these different things.
The custom field has a character limit. It should be unlimited like "note from buyer" for instance.
Those were the main features I would love to see integrated into the system. I am currently using Shipping Easy and would love to make the switch to Ship Station, but I am finding it very difficult to do so when these features stated above haven't been integrated even though they two softwares fall under the same umbrella company. They should take from one another and make the best software out on the market!