-snip-
Okay. From the comments we have more points. So far we have...
1. Blockchain size for storage and downloading;
2. Number of transactions causes impractical updating of the blockchain because of bandwidth limitations;
3. Impractical confirmation time without a fee;
4. Unreasonably long confirmation time even with a fee;
5, (more?).
1. Blockchain size bloat isn't so much of an issue for storage space any longer. Pruning would be fully enabled by Bitcoin Core 0.12 and there isn't too much of an security risk of average users not having the full blockchain. Bandwidth is however, a problem though. With storage space and bandwidth becoming cheaper, there is little worry for this.
2. I don't get what you mean. If you meant that the blockchain is not able to handle a high TPS, a block size increase could eliminate this issue.
3. Bitcoin fees are relatively low. It makes no sense to not pay a fee.
4. It's a problem with varience, there is no fix about it.
Bitcoin fees are low at the moment. If the price keeps rising and miners keep making empty blocks, the mining fee will rise. For some people the fees may really become a turnoff. Especially because they don't normally see the fees in their daily transactions. In bitcoin you are constantly reminded of the fees with every transaction.
1 and 2 are really not an issue. Storage space is growing faster than a blockchain could ever do, and bandwidth is improving around the world.