Nothing horrendously wrong with taking a tight/somewhat conservative approach when you have a big stack. But it may not be the optimum way to win in the end. The problem with being too tight/conservative is that you get in the final three or headsup with a smaller stack. You want to position yourself to have a stack you can fight with in the end.
I love to watch others knock each other out...but everyone time one gets booted, the other's stack increases. If I am the one knocking out the competition, then it is MY stack that increases!
Personally, I play a tight/aggressive style until I'm in the money. But I am not scared to play suited connectors and small pairs when the preflop pot is offering me decent odds
or the cost to play is cheap. Bottom line is that you have to give yourself a chance to win...and too tight/conservative will often leave you shortstacked in the end.