In 3050, things were pretty much balanced. The Clans had superior technology, superior skill, but fought with an honour system, and had fewer numbers. If you took out the numbers or the honour system, the Clans would have steamrolled the Inner Sphere, because at the time, there was very little level 2 technology around. It existed, but it was in short supply. To give the Clans level 1 technology as well, you’d have to have all or certainly far more Clanners invading, or have the use Inner Sphere tactics to keep the war balanced.
Though, no matter what you do, in the end, the Inner Sphere’s superior numbers, superior economy, and shorter supply line would make it nigh impossible for the Clans to successfully conquer the entire Inner Sphere.