Perhaps we are thinking of different things when we talk about dribble penetration. There is the type of penetration that leads to takes at the rim, and then there is the probing penetration that a point guard like Nash or Rondo typically uses to get his teammates open. Vasquez does the second kind very well. He is good at maintaining his dribble and gets into the paint, but maybe not all the way to the rim. The key being that once the ballhandler gets into the paint, it causes the defense to collapse and frees up shooters. IT generally turns the penetration into a layup. Ditto McCallum. Vasquez uses it as a kickout pass opportunity more often than not. Both are effective at breaking down defenses. Once McCallum learns when to go for the shot and when to maintain the dribble to free up teammates, he will eliminate many of those blocked shots at the rim.
we are definitely thinking of different things when we talk about dribble penetration, because, in my opinion, dribble penetration requires the actual threat of a score at the rim in order to sustain its impact on a defense. against bad defenses, sure, simply maintaining a dribble may draw enough attention in order to free up a jump shooter, but make no mistake, the very players you've cited--steve nash and rajon rondo--have gotten to the rim anywhere from 300-600 times a season in their respective primes, and they've been able to score at the rim with elite efficiency...
in his prime, steve nash was a very fast PG with tremendous vision, and that significant
scoring threat he posed is what justified a good defense's attention as he slashed into the paint, freeing up open shooters to receive nash's laser-guided kick-outs for the score. but a roy hibbert-led pacers defense, for example, doesn't need to pack the paint in order to stop greivis vasquez's dribble penetration, not when they'll be able to stop his unathletic push to the basket with very little effort. in the event of vasquez penetration, hibbert may slide over to help, but i'm sure indiana's wing players would much rather just stay home on the kings' streaky outside shooters, forcing them to make bad/tough shots, or forcing vasquez to make a bad/tough pass. in an increasingly guard-driven league, it is my opinion that a playoff-caliber offense requires a serious threat to penetrate
and score at the rim...
all that said, i still expect the kings offense to be considerably more organized this season under coach malone, and with the direction of vasquez as a starting PG. the kings' shooters should, indeed, find more consistency from range in the absence of keith smart's junk ball style of play. but i also expect the ball to clang off the rim a whole helluva lot any time the kings face a competent defense, because until demarcus develops some reliable go-to moves in the post, there isn't a single player that the kings can count on to beat the defense with the ball in their hands...
a player like tyreke evans carved up both good and bad defenses with his ability to score nearly at will off penetration. he won't be doing so for the kings anymore, so the front office needs to acquire someone who can. nba defenses are increasingly more athletic in their composition and sophisticated in their schema. the teams that make it to the playoffs, and go deepest in the playoffs, have a good defense and at least one talent with a significant rim attack. if you can shoot the ball, so much the better. memphis can't shoot, so they fell by the wayside. san antonio can, so they made it to the finals...
but personally, i'd rather take my chances with a sturdy defense and an offense that piles up its points in the paint over, say, the shooting spree that is the golden state warriors. as fun as they are to watch, and as much as they're currently the "team to watch" in the nba, they got bounced from the playoffs this last season when the shots stopped falling and when they couldn't stop anyone at the rim. there's a reason they're hoping and praying for a full season of health for andrew bogut, and there's a reason they're absolutely ga-ga over the andre iguodala acquisition. he gives them a player who can defend out on the wing
and score at the rim, two facets of the game that plagued them in the playoffs, when a sturdy san antonio defense stayed home on the shooters...