I find the blob is good for stopping those characters that just stay higher than you, it never hits them, but it “slows” them, letting you get in a better spot or out of harms way…
About Dizzy…
The person I most often play GGXX with plays Dizzy a lot, and uses a LOT (A LOT!) of her projectiles, getting around them is sort of tough… but not always…
As you probably know, the blob stops most of Dizzy’s projectiles (except that DAMNED air-spike, which it sort of “slows” down, which is also pretty good…)
Anyway, in my experience against dizzy, the best way to get past the projectiles (usually the person I play throws a air-spike, and when you are sort of temporarily helpless, throws the 3-hit delayed biting fish)… is to… dash, dash break, fall just after first projectile, iad over the second projectile… and that gets you close to her (those projectiles have slowww recovery), but I don’t think you can do the normal iad. K, S, H / S, H iad K, S, H / S,H,ChemLove… maybe you can. I’m pretty slow, and Dizzy’s pretty short, so I don’t know. 
If you’re closer, well, chem love, dash and whack, whatever works…not really an issue.
That spinny large circle-deal… haven’t really figured out a way around that… but it’s pretty slow and you can usually just jump over it, I never usually gain any ground though…
Most of my issues against Dizzy are with her stupidly fast air pokes, but again, that can be stopped if you blob before hand… FRC’ing the blob is pretty important, though, since Dizzy has dbl dashing
Also, her iad.K,S,H, / whatever you want here, is SO fast… blows my mind. Not that safe, though, since there’s no dash brake…
I have an I-No FAQ up, but it’s sort of useless for this type of thing so far… I need to put some more work into it and make it at a more competitive level.
If there are some goodies in this thread I might add them to the FAQ…
Also interesting to note that EX I-No has that vertical Chem Love that deals with what jchensor said… I never realized that until now.
Hope this made sense.
Also, seeing how chensor is a strat/combo demi-god, I probably can’t really help, or everything I said has been tried. 