One of the biggest downsides to the use of canals is that locks take quite a while to cycle. Another downside is that locks transfer water from the top canal to the bottom, where it is lost. These can be ameliorated through the use of a boat lift (some of which are hydraulic based) as an alternative,
but the simplicity of the lock is lost.
So, I propose the hydraulic lock. A reservoir will be dug adjacent to the lower canal, to the same depth and volume as the lock. The bottom of the reservoir will be connected through pipes to the sill of the lock, which will be perforated. When the lower chamber is open, the reservoir will fill with water, to the same level as the lower canal.
Over this reservoir will be suspended a heavy weight, which will form a seal with the reservoir. To raise the lock, the lower gate will be shut as per usual and the counterweight lowered, forcing the water in the reservoir into the lock chamber. As the water is entering from the bottom, and through a large area (perhaps 25% of the sill will be open), the water level can be raised quickly without jets of water that cause damage and severe turbulence. To drain the lock and go from the top canal to the bottom, a pulley will lift the counterweight, allowing the lock chamber to drain back into the reservoir.
For added speed, guillotine gates can be used instead of mitre gates. This type of lock system should, also, lend itself to a shaft lock to achieve a higher rise, important as the gates will become a larger portion of the time taken to cycle through the lock.