This is simply not true. If you will go back to Kiffin's year and remember they had the Sullins brothers blocking at C and G that weighed a grand total of 260 lbs. each. Played well enough to win 7 games and go to a bowl.
Technique matters greatly in a timing (Jones) offense no matter the size and strength.
The depth chart from the 2009 Va. Tech game:
TE Luke Stocker (Jr)*, Jeff Cottam (Sr.)
LT Chris Scott (Sr)*, Dallas Thomas (Fr)*
LG Cory Sullins (Sr), Vladamir Richard (Sr.)
C Cody Sullins (Sr.), Cory Sullins (Sr.), Josh McNeil (Sr.)
RG Jacques McClendon (Sr.)* William Brimfield (So.)
RT Aaron Douglas (Fr.), Jarrod Shaw (Jr.)
WR Gerald Jones (Jr.)
WR Denarious Moore (Jr.)*
RB Montario Hardesty (Sr.)*
RB Bryce Brown (Fr.)*
RB David Oku (Fr.)
RB Tauren Poole (So.)*
FB Kevin Cooper (Jr.)
FB Austin Johnson (So.)*
QB Johnathon Crompton (Sr.)
*denotes current NFL player
I agree that technique is important, wouldn't you agree that the technique of a senior in the vast majority of cases will be better for a senior than a freshman?
In 2009 we had a senior NFL LT and a senior NFL RG, so on both sides of the ball we had guys with a ton of experience to help the new guys as well as an experienced NFL TE to help Douglas as well.