I guess you're talking about this:
http://www.enworld.org/forum/4480547-post18.html
Since apparently no official response has been given about the power, general consensus has it that the indentention makes it so. As with most powers with an indentation, if the "Hit" clause is true and you meet the requirements then indentation happens, since there's no distinction (for example: "
Hit: 1[W]+ str modifier damage per attack."), if "Hit" clause happens twice, then indentation also happens twice.
Yes, it's pretty broken, even more when you consider that when the time to replace Powers come (where you can replace a lvl 3 encounter with a lvl 13, for example) and it's just not worth to replace it...and when you realise, it's lvl 29 and it's still not worth to replace it.
A level 3 encounter power shouldn't be more powerful than a lvl 29 daily (or really, more powerful than ANY other fighter power, in terms of single target damage at least).
On this thread
Fighter Level 3 Power Rain of Blows - Wizards Community it's been suggested an errata for it (where it's due).
Now, IMO, even if it was "just" 3 attacks, it would still be too powerful for its level. I mean, I'm not that familiar with ranger powers, but if you take a look, compare Rain of Blows with Triple Shot (a lvl 17 encounter power).