Cutting into the ceiling will cause some damage, but how weak/'blown' is it? I have never caused major damage to one yet.
If the old cables are flat 2 core cables that haven't been fixed to the above joists then you should be able to use most of them as draw wires. The switch drops may not be so easy. If the wiring is in very narrow lack metal tube it is unlikely you will be able to use these. Newer conduit will be ok, as there is more likely to be an inspection box at each point.
Wall lights would solve the ceiling problem, as all the wires can run under your floor, assuming it is floorboards. Then you have the problem of chasing channels into the wall. If you do this, use oval conduit, for the NEXT rewire.
There are a lot of nice wall lights available now, including bathrooms.
A good electrician should be able to rewire the ceiling lights without too much damage. As mentioned, he will fish along the joists as much as possible, and will notch the ceiling under the joists where he can't fish.
He will also take advantage of any cupboards etc to hide cable in.
Adding a suspended ceiling would of course make work easier from the electrical point of view, and may allow you to fit recessed downligters.
If you did go to the expense of lowering the ceilings take the opportunity of installing any other wiring you need or may need in the future.
It may prove a quicker and neater job if you left the job to the electrician, assuming he is good and is experienced he should be able to install wiring in the ceiling with minimal disruption.