Could you be so kind as to offer a reasonably clear definition of what you mean by "projected ceiling" ?
Usually for these types of threads, projected ceiling is the highest level the players could reach (who will be best in their prime) given the skillsets that they have.
It is incredibly problematic, because it compares rookie Taylor Hall, to 50 goal Stamkos, to 2nd year John Tavares, to Junior player RNH. You have to try to compare their skillsets and determine who will be best.
At this point, I don`t see how Stamkos and Doughty aren`t two of the tops. Pietrangelo and Bogosian both have high ceilings with Pie being closer to reaching it.
Tavares is good, but not great (especially defensively) and has largely been outplayed by Duchesne (whose all around game makes him more valuable). Hedman seems like he will be at best the 3rd best D, but could easily fall below the three 08s. Kane seems to me to be Duchesne-lite.
Hall has the speed and flair, that once he gets it, he`ll probably be the 2nd best forward on this list. Seguin is a complete forward, but looks like he will be a 2nd line center. Gudbranson and Johansen are probably the lowest guys on this list (defensive D and defensive FW with questionable offensive upside).
Of 2011, Couturier looks similar to Seguin (2nd line C). Larsson looks like he`ll be a good two way D. Landeskog seems to have some offensive ability plus leadership (2nd line center who can also be a leader). And Hopkins looks like he can be a skilled 1st liner who is more of a playmaker than sniper.
If I were to order them in terms of potential, I`d say:
Stamkos (doubt anyone reaches where he is now)
Pietrangelo (has the tools to be a stud D)
Doughty (already has a Norris finalist season)
Hall (next year is his breakout year)
Duchesne (has all the skills to be very good at both ends)
Bogosian (being in Atlanta has limited what I think he will become)
Hopkins (he will be exciting to watch in 2 years)
Landeskog - offense plus grit
Kane - can play at both ends (has good natural skill)
Tavares - good on offense, not so much in his own end
Seguin - indispensable 2nd line center
Couturier - see Seguin
Larsson - is supposed to be Hedman with a better offensive game
Hedman
Gudbranson
Johansen
The bottom 3 are more defensive players, so their ceilings are likely lower, but they are also a lot more likely to reach their ceiling. (Note: not all players ever hit their ceiling, so Bogo could easily be the worst player for example)