I like him as a player. Philly will definitely have a tough time matching offers for their restricted free agents after getting Brand. I'm sure their full attention will be put on Iguodala so maybe someone could come in and take Williams from them.
Philly's contract structure (i'm no cap expert) actually seems perfect for them to sign Williams to a long term deal. i don't know how high they are on him as a starting PG, but my bet is that Mo Cheeks is grooming him to play that role.
and Andre Miller's 10 million dollar contract is up next season, so it would be a natural transition for him to sign a solid 5 year extension at around 8 mil per. it would not mess up the payroll at all as far as i can tell.
they would have long term deals to Brand, AI, Louis and Dalembert (basically their starting lineup) and very affordable rookie deals to Smith, Speights, Young and decent deals for bench/role bench players Evans and Green.
also Dalembert, Evans and Greens contracts are up when they would be looking to extend Young.....so their roster actually makes a lot of sense.
Miller/Williams
AI/Green
Young/FA (maybe a Matt Barnes)
Brand/Evans/Speights
Dalembert/Smith
they actually look to have a really fun team to watch.