I respect the fact that Cryptic needs to limit Inventory space on players so it doesn't cause server data storage problems, however, something needs to be done to reasonably help with items you almost have to keep on hand.
Commodities, a mission related item, critical to have on you if one of your random exploration quest pops an "Aid the planet" mission. From the Starfleet view point, having these vary items on hand to preform these helpful acts of helping others out, makes it necessary to simply start out with this items in your inventory, pretty much the second you leave the beginning borg missions. It is rather irratating to get done with the newbie starting missions and then fly to an exploration quest for the very first time, to get the "Aid the planet" mission, and in the happy go lucky style of saying "ok cool" you find out that, you don't have the supplies you need to do it at all. And to top it off, you didn't have the credits to get those supplies from the vendor at starbase.
So, enough Commodities need to not only be given to you at the start, right after leaving the newbie borg quest, but they need at least enough inventory slots for their own, to handle at least 1 full stack of each single type of commodity the game will through at you, at that level. 3 slots at the beginning to handle the 3 single stacks of Shield Gens, Provisions, Medical Supplies a normal traditional starfleet crew "WOULD" have on them, simply because that is how starfleet chose to be (was storyline engineered to be). And not even a full stack either, only start us out with only 10 of each, only enough to finish 1 Shield Generator Aid the planet, and ect. Keep the commodities up after that would be the responsibility of the player.
As the player levels up and more "aid the what ever" missions require more then just the first 3 commodities, the "Commodities Inventory" Special slots would expand to be able to fit 1 full stack of each unique commodity. But only the Commodities Inventory space would expand, you wouldn't be given but maybe 1 of the new type of commodity, to help let the player know that there will be new "aid the planet missions" from the new places they can get "explore that space" for.
I also think that the same should be done with the Data samples.
3 Ens lvl characters
And what ever many slots R.Adm. will need to carry at least 1 full stack of each unique data sample that can be found.
It is very likely that a starship would have such managed use of cargo bays, knowing before hand that they will have things to deal with that will require quick and easy access to supplies. A ships Armory and weapons control systems are going to be separate from the rest of the ship, the medical supplies will be in or stored very near the medical bay, the shield generators and communication arrays as well as other ship maintenance supplies will be stored close to or in the engineering section. So it simply makes since to have special player inventory slots of "Commodities Inventory" and "Data Samples Inventor" in addition to the preexisting "player normal inventory," and expanding as you level just the same.