Didn't they put in a chicane at the NW200 a few years back that caused more problems than it solved?
Where would you put them?
If you had 5, 10, even 20 chicanes there would still be places where they would be travelling at 150 - 200 mph.
After a crash at the Nook someone suggested that they take out the hedge and put in a gravel trap. The counter argument was that you would be turning it into a 37 mile short circuit, and where would you stop? It wouldn't be practicable over the whole course.
There do though seem to be accident black spots. I presume that the organisers know of this and assess the situation to reduce the consequences of any spills.
Anyway the TT is ridden on public roads, and as such they have to be maintained firstly for the benefit of the IOM residents.
As a consequence of changes lap time might not bear direct comparison to those of years ago.
But I don't think that matters, all you can compare things to is the riders performance over the past few years.
As for straw bales I think that is a financial thing, how much would it cost to put air bags all round the course? That's unfortunate but a fact of life.
Putting in chicanes would probably not have much effect on newcomers, but experienced riders would need to learn the course all over again. It would not just affect the corner where the chicane was but their line and speed into the next corner and the one after that etc etc.
I would be interested to know which locations on the course you were thinking about.