As a former cannon-cocker myself, I attended the same artillery schools as did army arty officers. Our doctrine is almost identical. Other than the army bought into "big sky, little bullet", and we didn't. Which our pilots liked.
But the Army does have more arty, and more varied assets. So it certainly is possible for the army to put together a more flexible package of arty support for a given operation if it has the time and assets in theater to do so. We just don't have the equivalent of Corps-level artillery. Although that can be task-organized to some extent by adding more arty units to a particular MAGTF package.
The way I've always looked at it, both the Army and the Marines have a particular value that could not be fully replaced by the other. If the Marine Corps tried to get as large as the Army, it wouldn't be the Marines anymore. And if the Army tried to recreate what the Marines have (and they've looked at it one some levels) they couldn't do that either.
We're all on the same side, and in the same boat.
I attended the FAOBC, Lance and MLRS courses at Ft Sill from 1988 through 1992. There were a lot of squared-away Marines in those courses and some of the better instructors were Marines.
As for "big sky, little bullet"; I think that was always a fire support trick by the Army artillery in order to prove themselves over other fire support assets. The first thing fire support planners at V Corps headquarters would do was block out their boxes and keep the aviation guys at bay.
I'm not against the "expeditionary" aspect of SOME engagements (which the USMC clearly owns), but the prevailing trend to declare everything as expeditionary has clearly been proven false. After two years, EVERYBODY wants heavy assets and the lame attempts to bolt ineffective "armor" on HMMWVs is no substitute.
The problem with the Army is that we still have aggressive recruiting goals for non-combat arms positions. Let's face it, CS and CSS branches don't attract the hard-chargers that the Combat Arms branches do. Coupled with the Army's inter-gender experimentation (thanks to politicos and gutless General Officers) and we definitely have a problem. The Army can clearly use the very successful USMC model of gender separation as justification for returning to single-sex basic training.