You are describing the offline collection by design.
If you are collecting in online/live mode, it will try to save the feature(s) when you hit submit. If you want to save them "locally", then sync it back at a later time, that IS Offline editing. besides, when the network is slow, it will have issues with the basemap data as well, not just the edited data.
I have the background loaded directly on the the device, create offline area and download to device.
This way, the basemap doesn't need data connection, and neither does the edited data until you are ready to sync your edits.
Go to field, collect all the data I want, return to office, connect to "faster" network and sync the new edits that are stored onboard for later.
As far as failing for large areas, need to remember this is ESRI, and stuff like that you will have to learn to live with and adjust your workflow accordingly. (aka, the "Workaround")
R_