Some random stuff that came into my mind recently about the 1.5 beta version:
Cheaper exploration of planet surfaces and higher chance of finding something- excellent, I do exploration well before late game as now I can afford it
New artifact properties- paired with the cheaper exploration, singleplayer fun factor increased over level9000 
Titan research level1-3- it is a magnificent idea to do something about these otherwise boring stuff, they didn't really do anything interesting in the past, but now even the small increases here and there are making me think, yeah it would be good to research titan construction cap levels because they are doing something nice too (even if I am far from actually launching the mega project of a titan-construction queue)
Vasari as balanced as it never were in Rebellion- still the two strongest factions are the VR and VL (it is very very sad
), but they are not that extreme now, thanks for it.
TEC terran pop increase- it is off the charts in awesomeness, with 2 civilian labs I can increase 30% population, cool 
TL and it's new early research- I find it quite attractive to research now, it is cheap and gives an edge in experience point collection, good
AR and it's earlier research for the decreased cost of temple of communions- it was a good idea but still, too late I think, level1-2 would be the ideal, because culture is a marginal thing in Sins, and you only need some culture centers to maintain your color on the lines, and it only pays itself back if you build 3 or more culture centers AFTER THIS RESEARCH... risky investment..
Nerfing wail- I haven't tested it myself, but it really seems too much of a correction, it is now a risky move pushing the button on the temple of communion as even higher population planets do little damage..
AR and the plasma upgrade from the titan research- really? why? why plasma? It would be really awesome if it was +20% (or even higher) psionic surge attack rate or damage instead.. Plasma seems to be a useless addition, only helpful when you are using heavy cruisers... if you want to build them.. other bigger things rarely use them as main weapons (except the starbase, maybe it was the reason for it? yeah it should be)
Range increase of flak frigates- ... one step on the right path, but still it is very small adjustment, they need way more love to be able to handle late game bomber swarms, maybe something high level research allowing them to use some kind of mass control ability? slowing them down, damaging them, slowing their weapons, messing with their targeting computer (chance to hit decrease) etc etc, many good ways of enhancing these ships.. But it is a good change, could be more, but good.
New planet textures- yeah awesomeness level off the charts, I hope their polar regions will get as nice as the other parts.. The desert planet has way too much city light I think.. Same goes for the dwarf planet, who the hell wanted to live there in high numbers? even making cities there??
funny. The terran lights are weird, many does not match the landmasses.. I hope these are just previews to please people, and in the final 1.5 version they will be complete as possible 
Changing the solar system travel research place to be 1 step later- well I did not expect that, but I'm sure there was a reason for it, though I don't really understand why..