This guy is a tad obnoxious but he's got a decent breakdown of the new Symmetra.
Highlights: her chainsaw is no longer autolock and now functions more or less the same as Zarya's cannon (just retaining Sym's original charge-over-time/damage mechanic), so that's my biggest and oldest complaint solved right away. Her alt-fire works kinda like it did before, it's just faster now, and has better splash damage, which for my money is a good trade for losing the primary lock-on.
Her turrets are now launched from a distance instead of placed at arm's length, which should give them some nice new utility 'cause they should be able to reach interesting new places now, instead of just being limited to blind archways or hidden inside bushes. Total number reduced to 3 from 6, but they're harder to kill, seem to have better range/power/slow, and those launch tricks will be a lot more fun and dynamic, situationally anyway.
The old shield generator ult is gone, replaced by a supermassive fuck-off 5000HP barrier that splits pretty much the entire map in two.
This thing is absolutely ridiculous and I can't wait to see if it totally changes team fights and holds or ends up being easier to work around than expected. Without actually seeing it in a proper fight I have a hard time visualizing its exact utility in my head.
The biggest/best change though is probably moving her teleporter from ult to a standard ability, plus it now works kinda like Portal instead of always keeping one end in the spawn room. So, one entrance will always be placed at Sym's feet, and the other end you can aim as you would a Reaper teleport, basically. This will allow her to provide quick two-way access for other characters with low mobility, open up some weird unexpected flank routes (especially through vertical spaces), and certain abilities (even ults!) can travel through the teleporter,
including blinking/recalling Tracers, charging Reinharts, boosted D.Va self-destructs, and Junkrat's riptire.
So uh I'm really liking the new-look Symmetra so far, even if I'm not necessarily gonna become a Sym main overnight (nor would I expect to see her become a high-value pick in OWL Season 2), she's at least far better positioned to make the rest of her team better via her reworked teleport and when I get her over and over again in Mystery Heroes at least I'll have some new kit to look forward to.