Ahh, ic. I believe at the moment the mechanics allow for 'bubble streams' that do not suffocate players or mobs. As long as mob behavior isn't changed along with the water mechanics this would be a viable alternative to the traditional mob elevator.
Using ladders works, but you need to have like 20 mobs pushing to get them to go up. With entity cramming this gets to be a delicate balance, and you could potentially loose skellys at the bottom of the elevator when you get a stubborn one.
Once the 1.13 update hits console version the sign trick won't work, as you are aware. In order to give us an alternative to this tried and true design mojang has made it so that if there is a column of water above a magma block it will make bubbles. It has been shown that players can breathe in these bubble streams and do not take damage (from the magma block) when the magma blocks are submerged, and can swim normally, and it is assumed that mobs will behave this way also. So to fix your water elevator you would replace all the signs with source blocks and place a magma block as the floor of the elevator. This would allow mobs to swim to the top in a solid column of source blocks without taking any damage, preserving most xp farm designs that use a water elevator to raise and then drop a mob from a specific height to do a specific amount of damage.
What is not known is how mojang will allow us to chain water streams together. Now we use top half slabs (for item steams) or signs/fence gates (for mob conveyors), but this will not work in 1.13. It is expected that there will be some kind of block that will ignore the new mechanics to allow us to continue to use water elevators/mob and item streams. However we do not know how thats goanna play out, whether it will be an existing block or if a new 'gate' block will be added.
For what its worth, it doesn't look like this update will be coming to any Minecraft edition any time soon. Mojang has already announced that they have pushed back they're internal deadline and rolled what was supposed to be 1.13 and 1.14 updates into one. There is no published timeframe from Mojang for the release of the update, and the snapshots (released to java edition) are still not even close to implementing all the features that have been shown by Mojang. This is a huge deal, possibly the biggest change to the game ever, and the devs are trying to balance these new features with existing features so as not to cause an upheaval in the community like the 1.9 combat changes (which they are now reconsidering).
I was aware that they rolled it into one. Yeah, I forgot about magma blocks until now. I wasn't even thinking about item elevators. I wish we, the console players could hold torches in our off hand. I hope we get a block that ignores it though. Yeah, I'm just trying to do as much as I can before the update happens so I don't have a lot to fix when it drops.
I know what you mean. My survival world is over two years old and covered in contraptions. I always have something that doesn't work right. When we get this update its goanna take me six months to fix everything. I have close to a kilometer of water streams to move items around.