40k 8th Edition Unit Customization
Has 40k lost a lot of its customization and character options?


Yes and no. In Matched play your options are much more limited, but in Open, and to a lesser extent Narrative play whatever your opponent agrees to is fine!


  Are the expected codices supposed to give more options/customization?


We hope so, but there isn't any definitive word on this.


  Can I take a unique item or character and modify it for my own use?


Absolutely. When and where you can play with that character will depend on how closely you hew to the Index/Codex and how strict events you go to are. If it's not an organized event, talk to your opponent first, and for anything custom strive for underpowered!


  If so, and WYSIWYG still applies, how would I compute costs fairly?


Something outside the rules probably won't fly in a Matched Play organized event. If you're playing with power, it shouldn't matter too much, but you might want to add a Power point or two to the cost of the unit to compensate.


  Would it be fair to just double the cost of the normal version?


Maybe, maybe not. This is way to situational to answer.


  Is this something that I should not be as worried about in actual gameplay and just give them what I can from what exists?


Probably. If you have a regular gaming group talk to them. If you are planning on going to tournaments stick to the rules