SQL Server: extremely slow table on a simple select - sql-server

Question

I am dealing with a SQL Server on Azure, and I found a rare case where queries over a single table are really slow, over 10 - 12 seconds for a table that has about thousand rows, and while similar tables respond in less that 1 second.
Table definition (script create) is:
CREATE TABLE [dbo].[Content]
(
[ID] [int] IDENTITY(1,1) NOT NULL,
[Content_ID] [int] NOT NULL,
[CultureCode] [nvarchar](50) NOT NULL,
[Version] [int] NOT NULL,
[UserID] [int] NOT NULL,
[Timestamp] [datetime] NOT NULL,
[Title] [nvarchar](max) NOT NULL,
[Subtitle] [nvarchar](max) NULL,
... 14 more [nvarchar](max) FIELDS...
[NotesPlainText] [nvarchar](max) NULL,
CONSTRAINT [PK_dbo.Content]
PRIMARY KEY CLUSTERED ([ID] ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
ALLOW_PAGE_LOCKS = ON)
)
(the columns Content_ID, CultureCode and Version seem to be a unique combination, even is not set in the table as that. [ID] is just used as row identifier)
Aside of 17 columns all nvarchar(max), nothing else weird.
As I said, no uniques defined, no index ...
So I tune up as
CREATE TABLE [dbo].[Content_optimized]
(
[ID] [int] IDENTITY(1,1) NOT NULL,
[Content_ID] [int] NOT NULL,
[CultureCode] [nvarchar](50) NOT NULL,
[Version] [int] NOT NULL,
[UserID] [int] NOT NULL,
[Timestamp] [datetime] NOT NULL,
[Title] [nvarchar](max) NOT NULL,
[Subtitle] [nvarchar](max) NULL,
... 14 more [nvarchar](max) FIELDS...
[NotesPlainText] [nvarchar](max) NULL,
)
CREATE INDEX IDX_dbo_Content_optimized__Content_ID
ON [dbo].[Content_optimized]([Content_ID])
CREATE INDEX IDX_dbo_Content_optimized__CultureCode
ON [dbo].[Content_optimized]([CultureCode])
CREATE INDEX IDX_dbo_Content_optimized__Version
ON [dbo].[Content_optimized]([Version])
CREATE INDEX IDX_dbo_Content_optimized__UserID
ON [dbo].[Content_optimized]([UserID])
ALTER INDEX ALL ON [dbo].[Content_optimized] REBUILD WITH (FILLFACTOR=90, ONLINE=ON)
and here where things get weird, I am not saving even a single second of execution.
Indeed code like this:
select *
from [Content]
where Content_ID <> 1049
order by Content_ID, Version
select *
from [Content_optimized]
where Content_ID <> 1049
order by Content_ID, Version
gives a 53% and 47% on the execution plan (just 11% faster because of the INDEXes)
Sure I am relative new to SQL optimisation, so there is something I am not seeing here that may be obvious, but I am right now lost on it.
Any help?