I like that idea. Phase in tax credits based on the student loans you have paid in the last X years, with higher weight given to more recent payments.
To be clear, even though I've just about finished paying mine off, I'd vote for full forgiveness in a heartbeat with or without that provision, but I think it would make it much more pallatable for a large chunk of the population.
The only thing to watch out for using a laptop that is plugged in 24x7 is the battery. Battery management systems are generally pretty good, but Li-ion batteries can fail catastrophically. As long as you make a point to check on it periodically it's probably fine.
I'm using an old laptop as a local interface for my network setup, since its in my basement, and I actually pulled the battery out entirely since I have a beefy UPS powering everything. Paranoid, maybe, but a Li-ion battery sitting on top of my equipment rack could do a ton of damage if it were to fail someday.