There are a lot of things I wanted to address regarding Brule while reading over this thread; so many, in fact, that I have forgotten many of them.
First of all, I see Brule all the time, but I think I can confidently say that I have very little bias in either direction regarding him.
I really don't think Brule will ever be a franchise forward in the sense that a Sakic, Forsberg, Fedorov, Naslund, Iginla or even Yzerman - to whom Brule has been compared - is. He will not dominate offensively at the NHL level, and his shot and hand eye coordination are his only elite skills. His passing, playmaking and vision are good for the WHL, but nothing special in the NHL, his speed and acceleration are very good but not great, and his general offensive awareness does not particularly impress me.
Despite all of this, Brule could become the kind of player who is a franchise cornerstone. Trevor Linden was never an elite offensive talent, was never among the league leading scorers, and never had the same skill that other guys did, but he was still an extremely important player for the Canucks (I am talking about the Linden of old here). Brule could become a similar kind of player if he reaches his maximum potential. Someone who can score but not with the best of them, will battle and grind with anyone, and do all the little things necessary to win. This kind of player is very important to a team, and although Brule might not win any scoring titles in the NHL, he could be among the most valuable players to his team. This is not to say Brule is like in playing style to Linden, only that they could have similar impacts in their primes.
Size is not a big issue with Brule. People must understand that size is not important on its own, and only as an indicator of other physical attributes like strength, power, strength on skates, and a person's ability to improve in these areas. Brule is not strong enough to completely overcome his size, but I don't think it will really hold him back a whole lot.
In comparison to other highly ranked players for the upcoming draft, Brule really should be a consensus top 3. I've only seen Pouliot a few times, but he does not look to be in the same class as Brule. The things Brule is doing in the WHL this season, a MUCH tougher league than the OHL, are significantly more impressive than Pouliot's accomplishments for Sudbury. The only reason I can imagine Pouliot is ranked ahead of Brule is size, and I don't think Pouliot is as strong as Brule anyway. I can't compare Johnson as I've never seen him, but judging from reports, monster_bertuzzi is probably correct in saying it's comparing apples and oranges, and it will probably come down to team preference.