The Suggestions tab will re-open when the management and development team agree that is feasible to do so. The reason the tab is closed at the moment is because we received an abundant number of suggestions the first time around, and we genuinely care about finding ways to implement as many of them as we can.
If the tab was left open all the time, or reopened before the current batch of suggestions were able to be worked on, suggestions would be flooding in faster than they could be taken into consideration by the developers, leading to far more of your guys' suggestions being neglected - which is not what we want.
If you have ideas that you want to suggest, you are encouraged to hold onto them until the Suggestions page is reopened again in the future. That's a far better option than having the suggestion tab currently open and having an idea that you worked hard on get lost in the fray. Your patience is appreciated, and hopefully this clears this topic up a bit.