I wouldn't say that being large and powerful is a deficit in nature for 2 simple but HUGE reasons.
The largest and most powerful of a species is almost ALWAYS going to be the one to MATE/BREED the most, if at all, and they are usually in charge. Look at wolves, caribou, mountain goats, elephants, lions, gorillas, hippos, bison, zebras, mustangs, any herd of cattle. The largest also have the largest hunting grounds when it comes to solitary hunters like grizzly bears, tigers, owls, and even eagles.
Even our species subconsciously puts height and THE APPERANCE OF PHYSICAL POWER above nearly everything else when we 1st meet a male of our species. Many tribes of ancient man were famous for always being led by the biggest and baddest of the tribe. From the mongols to ancient Celts, there was no way that they would follow a "weakling". I have a feeling that even before that, it was the caveman who could best protect the tribe that was in charge, just like it is with almost every mammal species. When I served in the military, most of the guys who were looked at to lead were larger people. I was put in charge of the other trainees as soon as I showed up to EVERY military/combat school I had because of this. Granted I held on to the positions because of I had a good head on my shoulders.
I'll also say definitively that girls gravitate to the larger, stronger APPEARING guys in any crowd or group. Think about the big buff guy on the beach or the athletes in highschool that always got the cheerleaders... It's very rare that girls will go after a really scrawny guy.
Now, this is a generalization of course, and in no way a 100%. But...
With all that in mind, and truly believing that the ultimate goal here is to have a more enjoyable fulfilling life, I say: IF YOU WANT TO BEEF UP, THEN MORE POWER TO YOU!!!!! As long as you do it with a healthy mindset, don't sacrifice being cut for being large, and do it smart I can't see any reason to discourage you. Any info you need I'll be glad to help. (Hint: look at some of my fitness posts for what I mean)
Now granted, this is from a 6'4 265pnd heavyweight fighter and former military member, so my opinion is flavored from a drastically different life then your average 5'9 145pnd guy and obviously biased!