There is a 'rank' bonus, but its handled differently to in MTW.

The new engine has brought many new things, and obviously they decided to get rid of a few of the artificial bonuses (not difficulty orientated!) for certian things, like spear rank bonuses, and replace them with a more 'realistic' and graphically pleasing alternative. Rank bonuses simulated the fact that more then one rank can fight at a time, well now, more then one rank CAN fight at a time (eg. 3 ranks for standard hoplites) when in the correct formation. So whilst, for normal spears, no benefit was to be had over the max number of ranks for the bonus (IIRC 3 ranks) in RTW its the same, deploy your hoplites 2 rows thick, and 2 can fight at a time (at one point), deploy it 3 thick, and 3 can fight, deploy it 4 thick, and still only 3.

So the new bonus is more then one fighting at a time whilst maintaining a tight formation (something heavy infantry cant do). True you can make a long thin formation, and have it be effective, but you could do that in MTW too. The problem is, as soon as you puncture the row of spears, theres nothing else to keep them from attacking the spearmen, half the point of the additional ranks is it means 3 rows of sharp pointy sticks to wade through before getting to the spearman, who often has a sword as well (nasty shock, esp. to a MTW unit )