I will try the new list soon, and I welcome most of the gameplay changes. I am a great fan of simplification. These are merely some thoughts and questions from just reading the list, not actually playing it, and if I am wrong, you are most welcome to tell me so, otherwise I will have to find out for myself.
Hive Tyrants contribute +3 to spawning: Synapse (+3). So, if I have 2 tyrants in a swarm, according to the rules this give me a +6 modifier? If so, is not this quite much (as in more than a Dominatrix)? Does this not make Tyrants an infinitely better choice than Tyranid Warriors?
I have played the 8.4 M1.2 variant before, and I preferred some of the unit data in that variant, especially the Trygon. I think it is a bit inconsistent to give Carnifexes, Hive Tyrants and even Lictors Macro-weapons and not Trygons. My fexes' claws are tooth-pickers in comparison. This comment is purely aesthetic, but I still find it rather disturbing.
On a larger note, I have some questions regarding the nature of the Tyranid list. If I understand the history of it correctly, and also the underlying reason for a Phase III list, there has been an ongoing debate as how to make Tyranids more strategic in their gameplay. There is the option of winged tyrants, and I am just curious as to why the option is not there for tyranid warriors as well? Another option would be Trygon burrowers (deep strike). Trygons would then perhaps also belong to synapse creatures, as they do in 40K. Has Trygon deep-strikes been rejected, or tested?
Anyway, keep up the good work, and I am looking forward to trying the ONE Tyranid list for a change

/Fredmans