We'd love to hear about it! Click here to go to the product suggestion community
Being that the SSLVPN is based on OpenVPN could you please add a freeform text field to the SSLVPN page under Advanced that would allow us to enter custom server configuration parameters? Better still would be the ability to view and edit the entire config file itself but that may be asking a bit much.
Moved to https://ideas.sophos.com/forums/330219-xg-firewall/suggestions/38991679-feature-request-sslvpn-ui-improvements please visit that site and vote if you like the idea.