tcpdump?
tcptrace takes the output from these collectors and provides some time based statistics. but from what I've read, xplot is required to get a timeline of the individual packet interactions. I am in the process of loading it up to read the man page and give it a try.
I still don't think tcptrace was the tool I originally saw, but will check it out.
http://prefetch.net/blog/index.php/2006/04/17/debugging-tcp-... provides some sample output... but not the timeline I had in mind.
There's nothing simple about tcpdump/wireshark.
Wireshark does deltas for you if you want and can even calculate the RTT at every point in time during the lifetime of a TCP flow. Wireshark is fucking awesome and I'm sad you would say "simply provides..." :'(
But if what you want is just to know the RTT for a 3 way handshake against a remote endpoint, try something like gotcping: https://github.com/pjperez/gotcping/releases
tracetcp (and variants) is not what you want, because it calculates the time it takes for you to get a "TTL expired in transit" ICMP back except on the last hop. Gotcping and other avoid wasting your time by just testing the final endpoint.