Playing a spellsword, and with the class being as popular as it is right now, talking with plenty of spellwords around, I think I have a solid view of a few things that are harder to grasp on the glance.

I can summarize the imbues (based on how they work right now), like this:
Fire: Good if you are AB-starved or hitting super high AC targets (great for an offhand)
Cold: Great at low level. Once you start fighting things with more than 2 attacks, it drastically loses its use.
Acid: Even bugged, it's a great source of damage.
Negative: You can literally play without carrying a single healing kit with it. Less useful in PvP, but still amazing - specially if you find a target with low will
Sonic: Death sentence for a mage if you land your strike first, so be it in PvP or PvE.
Magic: Rarely useful. Magic damage is amazing and all (even though it still gets blocked plenty of times in PvE), but the dispel is just too unreliable to even hope to work. Even using a double imbue for 15%x2 chances, even using a dual-wield 15x4 chances, I still wouldn't use it. My guess is that magic literally works as a greater dispel, and takes into account abjuration focus, but I don't have anything to corroborate this.
Electric: Completely useless since the target bounces wherever the hell it wants. Would probably work better as stacking electric aura.
Also, yes. Did you know that once you get the Greater Imbue, you can stack the same imbue twice in a weapon? This means that if you normally are healing yourself 20 per hit~, it can scale up to 40. It still has to pass the saves, though.

The buff to Mage Armor made spellswords actually playable without EMA (which in my case, I don't get until level 29. Kill me!), but this also means that most of your AC can disappear in a simple dispel (at low levels), or a breach (at any level, which the more you level, the more common they become). Suddenly dropping 12 of AC can be a death sentence.
This spell, at least, should be unbreachable for spellswords, as they already have other weaknesses.

At low level, nearly any character can take a +1 tower shield for a gratuitous +4 AC.
As a spellsword, since you don't get shield feats, you can't. Which means that at low levels, you are stuck with an offhand AC bonus that is truly mediocre, and right until level 8 your AC doesn't get relatively any better, when other characters could freely start already assembling their gear or plotting with well-placed characters to sugar-daddy them. (Technically you can still get an addy helmet and a +3 cloth/plate, but since at level 15 these will cease to matter, it's not going to be an alluring option).
At least, the shield AC should have a +3 start, and upgrade to +4 at level 10, +5 at 20, +9000 at 30.

At level 21, you get greater imbue.
At level 22, you get your fourth attack.
At level 23, you get +1 AB and a wizard feat
At level 24, you get +1 Shield AC
And nothing more that is really relevant henceforth.
You get more CL, which is great because dispels suck.
Extra feat at 26 and 29, +1 AC, +1 AB, but multiclassing remains the best option because spellswords still get a very limited selection of skills, and if you want to survive in PvP (since Knockdown remains aggravatingly good), you still need to multiclass into something with discipline, and even better if you can get tumble and more feats.
I just like the concept of pure class builds, and there is no reason to build a pure class spellsword atm.

One of the main things the spellsword has is flat damage potential. An epic spellsword hits like a truck, specially if you know what imbues to use. Thus negating the main reason to ever go STR to begin with - damage.
Let's assume that you still want to build a STR spellsword, because you have too much pride to be a rapier-wielding spellsword dexer like the other 4000 players that made one before you.
So what's the actual thing that makes STR spellswords inferior?
ASF.
You have two options here.
A) You go the Still Spell route to deal with it (because let's admit it, the fun of a battlecasters is being able to stab things in the face AND throw spells within the same battle), accept to employ less metamagic because you can't obviously multi-metamagic, change the armor to rest (How I hate this feature). Eventually, in epics, sink 3 feats into Autostill spell and hate yourself for not building dex.
B) Disregard still spell. Use greensteel armor. You have to up your standard dex to 13 to use a maximized cats and raise to 18 to enjoy the full bonus of your AC, which, is somewhat hard enough. As a full caster, you still need 19/20 int for all your spells. And you probably want a good starting STR score. But you also want a good Con since you are going to be taking a lot more hits than the dex build. After all, your standard dex build will have about 34-38 final dex, which at best is 14 AC. Scaling down to a heavy armor that's -5 AC you aren't getting. You you have a greensteel armor, which isn't 8/1. It's 4/4, so that's -6 AC less.
Which also accounts for the loss of 2 stats, 8 skills. Or saves, or what have you.
As a dex character you can wear any cloth you want, and enchant it with, say, +1 int, +1 dex, +2 disc, +2 concentration, +2 spellcraft, +2 spot.
Okay. What of the good side? STR spellswords get a scaaaaary damage (if they go the full STR/Int route, which is painful I'll remind you), and they get more discipline and carrying weigh, which is cool, though they still seem to come up short.
Now, I've met two favored souls that multiclassed as spellsword.
These two characters, that had 0 ASF, weren't remotely broken or overpowered. They were merely better playable in comparison to the non-FS-Spellsword.
At this point I'm wondering: Does ASF still play a part in balancing the spellswords, or is it merely a stain that is worsening an already-bad build path.

Since spellswords don't get any epic spells or command abilities, their only actual epic ability that they get is the Greater Imbue. Which is great, but it feels like it could have so much more.
I know Kirito said that he was going to work on epic spell-imbues. I'm holding to my seat on that one!
I wouldn't mind spellswords having other 'tricks' and little niche abilities. For example:
A "force" ranged touch attack, based on the damage type of their weapon (bludgeon KDs for 3 seconds, piercing induces heavy bleeding and stat loss, slashing reduces movement speed, for example). Usable once/day every 8 spellsword levels.
Epic School Focus improves certain imbues (because right now there is little reason to take any school focus), IE: Necromancy increases negative imbue DC and healing by 1/3, abjuration increases magic chance by 5% per foci and adds +2 to dispel CL, etc.
That's all I can brain for now.