This is a yes and no question, are we aiming for quantity or quality. If it is more leaning towards quantity, then we need more troops, but the soldiers are usually ill trained and ill discipline. If we are going for quality, then what we need is elite, well trained and well equip warrior, such as special forces, but this take more money and more time to train. Currently, an average soldier take three months to train, while special forces soldiers such as Navy Seal, take up to one year to train, some other special forces could take up to two years to train and it cost a lot of money to train them. During WW2 and WW1 there are even less elite soldiers, during WW1 the less elite British soldiers only take 1 week to train, while the Chinese during WW2 also had a huge quantity of less elite soldiers, these soldiers only take one weekend to train. However, these british and Chinese soldiers were ill trained and ill discipline, the officers leading them into battle are frequently frustrated by their ill training. They existed, due to the huge casualty on the front line and the need to quickly have reinforcement troops.
The defense budget is limit so, it is whether u want to use that money to train a smaller but more elite army or a large but less elite army. U can't have it both way. Currently, most countries today, are moving towards smaller but more elite, this is mostly because, the armor today is so good, soldiers are hard to kill, so they can keep sending the same elite soldier back onto the front line, again and again, during the older day, it was more about quantity, because they had no armor, if u get shot, u are dead. And it didn't make sense to spend so much money to train an elite soldier, if he can be killed with one shot. Today, with better armor, it make more sense to have a smaller more elite army going into battle with super hard to kill armor, then to have a larger but more ill trained army. (A single special forces soldier, is worth an entire platoon, of ordinary soldiers.)