The only people who can update FPSC in a proper manner really are TGC.
Anyone who wishes to spend money elsewhere of course are quite entitled to do so - its their cash.
Personally I would not buy any add on, plugin or supportive software - at any price unless it was able to meet with its function fully. e.g. A Save/Load feature is just that - Save/Load anywhere/anytime - correctly. Anything else is just half baked and is no answer. Vice Versa - any software that did what it was supposed to do and was truly of benefit in meeting a missing need might be worth whatever value any developer asked for it. You then either buy or not if you can afford it - hard luck I guess if like me perhaps you cant.
Still I would in some instances be wary of purchasing a product from anyone other than TGC without proof in practical application that it could do what was claimed in the form of a working demo that could be fully tested in conjuction with actual development inside an individual users FPSC game making. Making software to work correctly in conjunction with FPSC which itself will currently cause problems is no easy task.
You should also consider than any update may see some considerable change to the current V1 source - anything purchased Now - may possibly not work correctly with FPSC when TGC eventually update the software. It may and may not.
I will personally wait and see what any update and future updates offer.
As to Save/Load and most eveything else you could possibly think of thats been already asked for inumerable times - you will get them when TGC decide it fits in with their future plan for their business and not before. We are extremely unlikely to affect their thinking along those lines.
Unfortunately however on based on current trends it seems you will just have to have patient until the next update and perhaps far beyond to find out what improvements you may see. The more you ask the less likely you are to be told anything.
Those that have been using FPSC for a long time waiting for an update or improvements are used to it and have some patience - If new users intend to make any decent game worthy of needing a fully fledged Save/Load feature then they should be still working on it long after the next update so they will have plenty of time to incorpoarate a Save/Load feature later.
Good luck with that.