Extending to the length of the current ramps at both
ends could be just long enough to fit two electric units, an extension from 120m to 152m being necessary for that. Even better than piers and beams would be the use of prefab concrete box sections just dropped into place.
The ramps would need to be relocated behind the platform for the north-eastern and south-western corners, in order to make the platform wide enough that people using mobility aids to safely get into position to use the first door - unless of course the EMUs will have push-button deployed ramps at all doors instead of the driver being required to get out and use a manual ramp.
Will it be worth it though, especially with the inevitable grade separation looming? There are other stations on the line that will also require the use of SDO (Selective Door Opening) to leave the doors locked on the last one or two cars as well, so they may as well do it at Oaklands too. I'm talking about Mile End (fits five cars only), the shortened platform at Marion (five only), Warradale (five only), Hove (four only) and Marino Rocks for Adelaide-bound trains (five only). Using SDO will allow double EMU consists to stop at those stations with passengers in the last car (last two at Oaklands and Hove) walking through the open connections towards the front of the second unit to where there are unlocked doors available.
Using UDS (Unit Deselect) instead of SDO would be the worst outcome, that would leave the whole second unit locked and half the passengers held captive even though only one or two cars of the second unit are off the end of the platform. To make it work with UDS being used at those stations would require the use of tedious announcements at stations which would get lost among all the other audio graffiti and would not get the job done if a service is unexpectedly a double consist thanks to some disruption
You may laugh at the possibility of double consists serving some of those stations, but you should remember that the extra trains running according to required capacity (i.e. not on a regular timetable) after big cricket matches with crowds of 20k to 30k stopped at all stations. It would be safe to assume that the same will happen with all double consists for the expanded Adelaide Oval hosting Australia home matches, Adelaide Strikers T20 home matches, the India v Pakistan match of the 2015 World Cup match and of course every AFL home game.