I run a MonoWhite and GreenWhite deck built around Champions and other Humans, so I can give you a range of advice... some of it may apply to your playstyle and some won't, but this is a great, underrated kind of deck and I think you could have a lot of fun with it.
1)
Gather the Townsfolk 
: Each token boosts your Champions plus gives you chump blockers. I've had this card (esp. it's 5-token variant) win games for me in a single turn by giving me a huge army lead and buffed-out
Champion of the Parish 
. 2-3x IMO, at least one. Also, you've got
Hero of Bladehold 
, which gives you Battlecry and some extra tokens (which, remember, buff CotP) every time you attack.
2) Consider getting some of the White soulbonding creatures to go with your CotP or tokens.
Nearhearth Pilgrim 
and
Silverblade Paladin 
can be pretty good in their own rights, and turn your (buffed out) CotP into scary, scary things while giving you some sustain (at least in the Pilgrim's case). Sometimes it's even efficacious to pair these two with each other, creating a double-striking/Lifelinking pair which will often be able to sneak past blockers trying desperately to keep your buffed-out CotP from eating them.
3)
Elite Inquisitor 
and
Grand Abolisher 
can absolutely wreck certain decks, and are respectable damn good in their own right. Double bonus if you have the soulbonding creatures I mentioned above.
4)
Honor of the Pure 
is a cheap, easy, stackable way to force-multiply your army (suddenly those 1/1 tokens are significantly more scary).
5)
Oblivion Ring 
is so stupidly good it belongs in any deck that can create white mana. It's basically a universal "annoying crap" remover.
6) I would strongly consider
Bonds of Faith 
over
Arrest 
, or at least a 2/2 split.
7)
Gideon's Avenger 
is another kind-of-snowbally human creature that's much cheaper than CotP if you're budget conscious. Sadly a lot of my advice is about pumping out lots of humans and human tokens and buffing them, so it's not a 100% synergistic fit, but it's something to think about.
Good luck! I like odd color combinations and this one could have potential. I feel you could utilize the red mana a bit more, maybe picking more flashback cards (
Devil's Play 
?), or of course a couple of
Red Sun's Zenith 
