I've played a pure DEX swash to thirty, and - It's definitely possible. And if that sounds like damning with faint praise, that's because it is.
First, the good news. Once you're all geared up, you'll essentially shrug off anything trying to hit you in melee; and third intention gives you a very handy panic button if you find yourself knocked down or on the receiving end of some particularly juicy damage spells. Perma-haste makes you as slippery as you want to be, and you can shrug off immobilising spells at the press of a button. It's easy to play, with a few useful panic buttons if you get yourself somewhere you'd rather not be. Parry can deliver some impressive hits, and under the right circumstances can let you take melee-types apart in PvE with relative ease. You'll have a higher-than-average AB. Fort and Reflex saves are solid, and Will can be patched with clarity in times of strife. With the dirty fighting changes, you'll have a range of entertaining and reasonably effective disabling tools to play with. You'll have a good spread of skill points to throw around after you get the essentials, and if you want to, you can grab enough climb / ride / sail to go wherever you want, really.
That is, unfortunately, where the good news ends.
Your damage is absolutely anaemic. It's bad. My PC carried a scimitar, and would crit for around 40 damage on a good day. The stat drain abilities you have never seemed to make a noticeable difference for me in PvP. A lot of monsters have high saves, which makes them very inconsistent and not particularly impactful. Gravity orbs make str-draining players less likely. Parry is situationally useful, but it's inconsistent in who you target, and the AI has a tendency to just stop hitting you sometimes, leaving you in an awkward staring contest until you can toggle to regular attacks to re-start things. You'll spend a lot of time sitting there, waiting for an opponents HP to trickle down. May God have mercy on your soul early on against enemies with DR.
I had my greatest success partnered with a rogue, who could take advantage of the tremendous survivability of the build to get off sneaks, but you'd pair well with any fragile hard-hitter, really. Playing solo is doable but very, very slow.
I can't speak to the strength build; but have heard anecdotally that it's superior. All that extra damage helps.
I've been out of touch with the meta for a while, so don't take the below as anything but a suggestion of something that is at least serviceable if, like me, you are resolved to inflict this on yourself. I played a drow, so swap around as you like.
Dex: 19 (17 + 2 Gift) | 28 at 30.
1: WF: One-handed Edged
6: Imp. Expertise
9: Imp. Critical: One-handed Edged
15: Dirty Fighting
18: Blind Fight
21: Blinding Speed
23: Defensive Roll
24: EWF: One-handed Edged
26: Epic Prowess
27: Epic Dodge
29: Armor Skin
30: ESF: Discipline
Skills: Bluff, Disable Trap (1), Discipline, Heal, Lore, Open Lock (1), Parry, Spellcraft (16), Tumble (30)
Remaining: 99 (I grabbed climb, ride, and sail, for the full swash experience.)