If you want this to play right, there's probably two short-term solutions:
1) Set up boot camp on your mac, reboot and play the windows client in windows. Max speed, compatibility, you'll have fewer problems and SSG support will probably actually talk to you. UPdating to macOS 10.15 won't cause you problems.
2) Run it in a VM, i.e. vmware or parallels. This may not work due to VM overhead, but you're still running it in "real" windows, not the "sort of windows" WINE uses. And again, you have some hope of actually getting support from SSG. VMware and Parallels both work in the next release of macOS, which is 64-bit only.
3) I'd say the WINE version, given how badly this transition has been handled, won't work consistently right for at least a month, and god only knows if they're using a 64-bit version of WINE. If they aren't, then you can't upgrade your mac because 10.15 is 64-bit only, 32-bit apps won't work, and you'll be unable to use the WINE version. Good luck in SSG fixing that inside of a year if ever. You'd be better off learning out to package it in WINE on your own and not waiting for SSG.
SSG is a windows-only company. That's their choice. But I wish they'd stop half-arsing this issue. Just say "we only support windows. Period." stop the WINE dance, because that is clearly not being done well, and given their apathy towards mac players for some years now, expecting them to get a 64-bit version out once 10.15 drops is unrealistic.
"Sorry Elminster, it was really dark, and I'd drank a LOT of coffee..."
We've released a new variant of the Wine client. The update is posted here.
This is not the same wine client as was previously being distributed in beta form. Many of the problems with the beta client have been addressed.
Please let us know of any further issues.
If I download the Wine client will it be a separate setup that won't interfere with my Steam client setup? I don't want to test it if it's going to mess up my working version I'm pretty good at troubleshooting, but don't want to waste time reinstalling if my Steam setup is going to get tromped on.
I know that previously, I was able to run DDO directly and it was a separate setup than the Steam setup, but I want to confirm this.