Space Marine Codex leaks show lots of nerfs.
no more built in double fire ability for Eradicators and Aggressors
Chapter Master upgrade costs 40pts and rerolls only affect 1 unit per round. Can't remember if it is limited to "core or character"
To get some of the bonuses from chapter leader upgrades you will have to also give the units a special warlord trait. Costs pts to upgrade. Because the best abilities are from traits you can't take 1 of everything and get full benefits from all of them. Although, the traits are better than before.
Centurions and Dreadnoughts no longer always rapid firing bolt weapons.
Who knows what else took hits.
EDIT: power level changes suggest some point increases.