Dane says:"Less dying is always a good thing. There will always be bold climbs and bold climbers pushing the limits. Bolts and new gear and changing ethics just make the limits of impossibility closer for all of us."
I agree with Dane.
Clearly tool and gear design has impacted climbing ease regardless of ethics at all difficulty levels. Even the better clothing and training knowledge has helped us climb with ease what was once thought of as hardman terrain.
Few ice climbers who started in the past 5 years (or even 10yrs) know of the days of guaranteed knuckle-bashing pain and the fear of having to place a screw that took perhaps as long as 5 minutes to place while hanging out on overhanging ice and knowing that the screw, which you paid dearly for physically, may not do you any good in the event of a fall.
For those leaders who hung from tethers to place screws, in effect resting, and then continuing "free", I'd argue that they were not freeing the routes but it was an accepted ethic at the time and necessary for many to stay safe.
Once a bent-shaft tool design hit the masses in the mid-90's, leaders suddenly were able to lead almost a grade harder with better clearance at bulges and a more relaxed grip position. Screws got better around the same time and now have become absurdly easy in comparison.
Prior to the bent-shaft tool, a small percentage of people were leading WI5/5+ or even M6 at that time. Now it's an everyday event, especially as routes get pegged out and easier with the increased traffic the sport has seen.
Lowe may not have invented mixed-climbing but he certainly inspired a lot of people to give it a try.
Sure, leashes are a trade-off on ice. Easier mentally because of the safety margin if you become pumped and you're on something you don't have the fitness or experience level or mental discipline for. On mixed climbs, especially bolted, it's a no-brainer. Leashless is easier.
Leashes or not, do what lets you have more fun.