Andrew's reform is destined to fail because he oversimplifies the problems in the army and expects too much from the reform. He borrows ideas from the French military code that can't perfectly fit in the Russian army. Meanwhile, problems within army are too complicated to be solved by an immature reform. On top of that, his proposal isn't taken seriously at all. Things could have been improved if people with power took in the ideas from outside and chose what can be applied.
However, I don't consider his efforts all for nothing just because the reform doesn't work out. From one aspect, at least it saves Andrew from depression and makes him think logically and try to do good for others. Notably, Andrew is given a powerless and not-paid position when he works on the reform. This indicates he doesn't care much about personal promotion and heroism as much as he did before. Andrew's personality is changing when he carries out reform. On the other hand, Andrew frees the serfs and builds schools and hospitals in his own estates. This is actually a remarkable reform, which Andrew has done naturally and successfully.
Using Andrew's failure, Tolstoy implies that nothing can be done with an individual's power, but that shouldn't be the reason holding us from taking action. Even if one fails, he has ruled out a wrong path toward success. And individual efforts adding up can make a big difference.
* Special thanks to Adriana Zenteno Hopp. She edited the blog. And feel free to point out my awkward expressions. I'd love to learn. :-)