You get so many skill points though, Buddy, you can afford to put them into a couple of professions, maybe even 3 if you don't take every single skill in the profession line. For example, with provisioning there's no need to get the hireling (it's shit), and it's best to focus on either food or beverages, rather than both. There's no real need to get keen eye in the others if you're the sort who enjoys exploring rather than relying on spotting materials while you're heading from A-B. The jury's out atm as to the benefit of the hireling in other professions. I've had a few blue improvement materials from my clothier, none from my woodworker (but apparently turpen may be bugged - no one seems to be able to get any other than from deconstructing blue items - I have 2 turpen and something like 15 embroidery right now). The only one that is truly necessary is the line that lets you craft at higher levels, the others are quality of life perks really.
As for bank/bag space, you're right, it's difficult, but there are ways to make tough decisions and keep it manageable. I keep most of the important materials on my character (wary of the bank bug) for woodworking and clothier. Provisioning materials go in the bank, but I'm not bothered about losing those because they are so easy to find again. Iron ingots and jute are in my bank, again if they disappear I'll not miss them. I currently have my runes in my bank, and some nice aspect runes too, which I'm slightly worried about, but they are for a different character and I'm avoiding logging into any of my other characters right now because that always seems to be a commonality amongst those who lose their bank slots (that's not to say it's definitely related, but until it's fixed I'm avoiding potential high risk activities - it could still happen to me though, of course).
I think there are ways and means to make multiple professions work, you just have to be very efficient, only hold onto what you know you're absolutely going to be using in the near future, and be prepared to spend time hunting and gathering for the other stuff when you need it. Making frequent trips back to town to deconstruct and sell gear and bank (currently low risk) materials helps as well, rather than thinking that you can keep questing for hours without having your bag fill up. I had to destroy an absolute ton of stuff from Cyrodiil last night because my inventory is at a permanent 40 slots full with the various mats I'm storing on me, and a few items I'm waiting to learn the traits on. That gives me another 40 slots to fill with loot drops, which fills up in an hour of PvE questing in Cyrodiil (heck, you can fill that in one dungeon).
I'm saving up to get my 90 bag slots on this character. I don't generally repair my armour, I just make new ones. It saves money. But I have a handful of really nice pieces at the moment, and since I'm level 19 still stuck in Auridon I don't have access to higher tier materials yet so I haven't bothered putting skill points into unlocking the next tier in crafting... I'll save that for when I can actually use them. So I replace the gear that is easily replaceable, and then I pay to repair the 2 or 3 nice items (remove the broken stuff from your inventory or the price will be to repair all of that as well). I sent about 50k AP on random armour from the AP vendor in Cyrodiil last night and ended up only keeping a couple of pieces. They were all blue, and I deconstructed what I didn't like/need. I have just under 6k in gold atm, and really need to focus on some questing today to get more for that bag upgrade.