I've flown thousands of hours IFR, and have never flown an A/C with TCAS! But agreed, there are solutions that will never be used due to the certification requirements. However, I still believe that a trip conducted IFR with the option to go VFR is still safer than going VFR with an option of limited IFR. If you can fly safely for 20-30 miles IFR, then you will be safer to remain IFR than to be required to descend into the clag again.
There are many ways of making a flight a little bit safer, but none to beat a good decision as to whether to set off in the first place. I've been lucky in the past that my poor decisions haven't cost me more than a few sleepless nights.