And who wants an antimagic field? I need my magic items too...lol
Hmmm...Interesting. A Gold dragon. I'll even help you out and say you only want to gate in one as you can only control 40HD worth of critters (2 wouldn't be as effective as that's a CR 13 monster and not much challenge for a fighter) I'll even give you the benefit of the doubt that a 40HD celestial gold dragon isn't a unique creature. Tough fight. In 2 or 3 rounds either the dragon or the fighter will be dead. Not sure which though.
So this is your main strategy is to attack me with the biggest thing you can find?

I was really hoping for something cool as you guys keep ranting and raving how awesome and versatile and everything else wizards are and how fighters are one trick ponies that just beat the crap out of you with lots of damage. It works but it took you a lot of effort(one 8th, and two 9th level spells) to just beat the crap out of me using phyical attacks.
Being some incorporeal undead inside your wall just lets me know where to find you should I survive the dragon though. The wall will be an easy smash thorough with a weapon and every good fighter wants to carry his Greater Truedeath Crystal
Oh and you can only use one rod per round even if you have 7 of them so you can leave it up to the dice or take your 4 rounds of actions.
Prismatic Sphere is just about making a few saves. Roll well and I'm hacking you to bits with no ill side effects. Roll poorly and well who knows. Depends on which save I fail..lol
Thoughts:
The general conundrum a warrior character faces in this matchup is this: "to magic it up, or not to magic it up?". If you want to be at all useful, you need magic items galore. If you don't have their effects up, you're useless. You need some form of True Seeing, flight, and Freedom of Movement at the very least. Otherwise you won't be able to see and get to the Wizard. Immunities to a lot of other stuff (negative levels, death effects, ability damage, mind-affecting etc.) are also important - pure reliance on saving throws brings in the problem of iterative probability and isn't advised really. So Antimagic Field isn't really useful, since the Wizard can just stay out of reach and use 'magic non-magical' stuff to bring you down, like some gated in creatures.
On the other hand, if you're that dependent on magic items, a single Mordenkainen's Disjunction will short out many or most of them. Making you just as useless. A lot depends on when you erect that AMF, and when you let it disappear again (all depending on getting a custom magic item that has such a feature in the first place - and if you can get a custom magic item, the Wizard can, as well). But whichever way you're doing it, the Wizard goes first, and you'll be on the back foot and reacting from that time on.
Another thing is gear and preparation. Even a Wizard with nothing but his component pouch and spellbook will likely be extremely well prepared for just about anything, while a Fighter simply
can't. Nevertheless, Wizards with good gear are even better, of course. Preparation, OTOH, doesn't do much for the Fighter (in that, he can't take good advantage of it if he has time to prepare), but will make the Wizard sooo much more of a pain...
To answer your points directly:
Took the Wizard just a very few spells to take down an opponent. He has almost all of his daily allotment to fall back on, should he need to. Depending on your magical defenses, he can MDJ your stuff, then put you in some inescapable battlefield control plus damage-over-time; or summon bunches and bunches of tough critters for you to amuse yourself with; or make you bend over and take it with mind-affecting spells for fun; or make you his own personal Wight with a bunch of negative levels; or reduce you to a quivering husk with ability damage/penalties...
On gating in Celestial Gold Dragons: I can use more than one Gate spell if I need more than one. I do think I can make do with one, though. Note that I just used a fraction of a CR 20 character's resources to bring a CR 29 creature to the field. Make further note that the dragon can cast like a 19th level Wizard, and can also use Cleric spells. It also has 717 friggin' HP - quite the meatshield. It also has 6 attacks at +51/+46/+46/+46/+46/+46, for 4d8+18, 2 x 4d6+9, 2 x 2d6+9, 4d6+27 (no buffs, no feats, no PA...). Average 134 damage if it hits with all (which it just might). Escaping its grapple will be difficult to say the least, should the Fighter neglect FoM. AC 41 (no buffs etc.) is hard to hit, too. That's one helluva monster for a single fighter to tackle. You know why it's so hard? Even if you have lots of magical stuff so your bonuses don't look too bad in comparison, this critter has no compunctions to use its own AMF to get you.
Finding the Wizard and getting to him: given you have True Seeing on, and the place where this hypothetical duel is taking place has walls that are impassable for incorporeal creatures, yes, you know where the Wizard is. Until your magic items are busted by MDJ and the Wizard 'ports to where it suits him better. Or until you simply find yourself within a Sleet Storm or similar spell that robs you of all vision.
You sure about those rods? Never mind, I'll take my 4 rounds of actions. Should be plenty.
'Prismatic Stuff' spells are quite reliable actually. You have to pass through them to be able to attack again - but if there's something on the other side blocking your move, you can't pass through. Wall of Stone immediately behind Prismatic Wall makes for a solid defense, nigh unbreachable. You'd need a Rod of Cancellation, costing you another round...
To sum up:
A well-built Wizard at 20th level is all but unsurprisable by anything a Fighter can bring to the battlefield. The Fighter, on the other hand, has to prepare for so many avenues of attack it isn't even funny. The very simple "gate in something that's a better fighter than the Fighter, then kick back and relax" is probably the strongest showcase of why Wizards are in tier 1, while Fighters are in tier 5.