It really all depends, no one can give you accurate feedback because none of us know exactly what the combat update is going to be like, my only suggestion would be for you to create a pure that you desire, once combat update is released, mold it into whatever deems best.
As for pure suggestions, there are lots of ways you can go. Either you're more of a fan of Melee, you can make a warrior, same for Range and Magic. However Runescape is so diverse now you almost need a hybrid (assuming you have experience switching).
Just mold your account as time goes on, for example, my pure now is 99 attack, 99 strength, 99 hp, 99 prayer, 99 mage, 99 range, 4 def (messed up with whip back in the day) plus it is a skiller.
You can't really ask suggestions on what pure to make because you nee the experience of every account, you need the experience of pking as a hybrid or else you're going to go in and get dominated by low level pures and it will ruin the experience for you.
Start a pure using things that you're comfortable with then train and learn more about it as time goes on but don't make a pure based on the combat update when no one knows how it's even gonna be!
Good luck!